Special Site for Activities Related to COVID-19


[Research Papers]

Collaborative Research and Online tools in the Era of Covid-19

KONDO Yasuhisa, Associate Professor

Journal of Rural Planning Vol.39, no2, pp.104-107


Published: September 2020


[Research Papers]

Jishuku, social distancing and care in the time of COVID‐19 in Japan

NISHI Makoto, Visiting Associate Professor

Social Anthropology/Anthropologie Sociale


First published: 18 May 2020

DOI: 10.1111/1469-8676.12853



[Director-General Letter ]2020/09/01

“Toward a Green Recovery - A thought on the summer of 2020”

YASUNARI Tetsuzo, Research Institute of Humanity and Nature

Soon after the long rainy season that caused heavy rain disasters in Kyushu and western Japan was over at the end of July, the record-breaking extremely hot summer started in August. Now, August is over, but we are still having the "dangerous heat" days with temperature exceeding 35℃ or higher, even around 40℃ throughout Japan. The number of deaths from heat stroke in Tokyo in August exceeded 200, which is the highest number ever recorded in many parts of the world, extremely high temperatures and associated forest fires have been reported. On the other hand, once cumulonimbus clouds develop, localized torrential rains which exceeds 100 mm per hour have been reported here and there. Under the COVID-19 situation, many children and students all over the country cut their summer vacation short and started a new semester early after a long school closure. Under such circumstances, the number of students who suffer from heat stroke is increasing because they are forced to go to school wearing a mask all the time in the brutal heat. The extremely hot summers have been increasing in recent years. Based on the data of monthly mean temperature in August in western Japan from the Japan Meteorological Agency (JMA) for 75 years since 1946, I have found that this year marks the highest, and the 7 years since 2010 indeed rank in the top 10.

Why has it been so hot then? The direct cause is that the Pacific (Ogasawara) high, which is a dominant atmospheric air mass covering over and around Japan, is very strong and the weather continues to be fine. This high pressure system is strong because the convective activity (cumulonimbus activity) from the western tropical Pacific Ocean to south of Japan through the Southeast Asian monsoon region is very active, causing stronger updraft there, and stronger downdraft in the Pacific high region through the north-south dipole pattern of the atmospheric circulation. Active convective activity in the Asian monsoon region is also related to high sea surface temperatures from the tropical Indian Ocean to the western tropical Pacific Ocean. The sea surface temperature is now rising globally as shown in Fig. 1, and has risen by 0.5 ℃ over the last 10 years. The temperature rise in Japanese coastal waters is even greater, and the sea surface temperature just to the south of Japan has reached 30℃ this summer, which is exactly the same level of the tropical oceans, where typhoons and tropical depressions can easily be generated and developed. The warmed sea water around the Japanese archipelago has increased the amount of water vapor in the atmosphere, which in turn, led to a long and active Baiu front in July and brought unbearable hot and humid summer in August. The increase in water vapor also strengthens the regional greenhouse effect and makes it hotter near the ground. However, once the atmosphere becomes unstable, it sometimes causes heavy rainfall never experienced before. The poor catch of pacific saury is very likely due to the rise in seawater temperature near Japan. It is reported that the global rise in sea surface temperature, including in the vicinity of Japan, is the consequence of the "global warming" that appeared in the oceans caused by the increase in greenhouse gases represented by CO2. (IPCC, 2013) The frequent occurrences of high temperatures and related extreme weather events and phenomena taking place all over the world can even suggest that the global climate conditions are approaching a tipping point where drastic changes occur. The Paris Agreement aims to reduce CO2 emissions to zero by 2050 in order to limit the global surface air temperature increase within 1.5℃ and avoid crises associated with the tipping point. Regrettably, this goal seems unlikely to be achieved, under the “business-as-usual” economic growth with the conventional social system.

Figure 1: Long-term change of global annual mean sea surface temperature (JMA, 2020)

Figure 1: Long-term change of global annual mean sea surface temperature (JMA, 2020)

However, this COVID-19 has provided an unexpected opportunity to human society. It has been proved that global CO2 emissions, which was increasing until January of this year, have been reduced by about 17% (compared to the 2019 average) in the subsequent three months due to the global slowdown of traffic, transportation and industry by significant restraint of movement of people after February in order to prevent the spread of the COVID-19 infection. (Le Quéré et al., 2020). The authors of this paper pointed out that even by changing the means of transportation for commuting and business trips to bicycles and public transportation from private cars and by stopping the private jet transfers by the wealthy class, it is possible to significantly reduce CO2 emissions. The socio-economic recovery from the COVID-19 pandemic should not just be a V-shaped recovery that attempts to quickly return to its original state, but it should rather be aimed for "Green Recovery*" which seeks the possibility of transition to a more sustainable new society, set off by the inevitable changes in society and lifestyle which COVID-19 has brought us.

Figure 2: Change in global daily fossil CO2 emissions by sector (MtCO2 d−1). The uncertainty ranges represent the full range of our estimates. Changes are relative to annual mean daily emissions from those sectors in 2019 (Methods).(Le Quéré et al., 2020)

Figure 2: Change in global daily fossil CO2 emissions by sector (MtCO2 d−1). The uncertainty ranges represent the full range of our estimates.
Changes are relative to annual mean daily emissions from those sectors in 2019 (Methods).(Le Quéré et al., 2020)

(Translated by Megumi Arita, edited by Tetsuzo Yasunari)

(Acknowledgment: I am grateful to Ms. Megumi Arita for completing the English version of this message.)

<夕涼み線香花火の匂ひかな> 正岡子規

<水を打つ曲りさうなるこゝろにも> 笙鼓七波
<海洋に打ち水をせん暑き夏> 哲風


[Activity Report]

Rethinking Air Quality and Climate Change after COVID-19

Joseph Ching and Mizuo Kajino*(*Main member of Aakash)
Meteorological Research Institute
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The world is currently shadowed by the pandemic of COVID-19. The death toll and confirmed cases have kept increasing in most nations. While COVID-19 is a monumental global public health disaster in human history, it presents various far-reaching and yet-to-be determined implications on air quality and climate system. Social distancing policy, suspended economic activities and traffic have been reported to improve local air quality of many cities. Conversely, a seemingly correlation between poor air quality and high death rate due to COVID-19 remains a question, and an increasing amount of studies has suggested that aerosol particles could promote the spreading of SAR-Cov-2 virus, the virus that causes COVID-19. The impacts due to public policy during COVID-19 on air quality and climate change could be long-lasting, and/or short-lived and their magnitudes and signs are currently subject of large volume ongoing studies. This article aims to provide a brief review of state-of-the-art research in air quality and climate change aspects and by raising some important science questions to inspire follow-up studies.

Ching, J. and M. Kajino, 2020. Rethinking Air Quality and Climate Change after COVID-19, International Journal of Environmental Research and Public Health, 17, 5167,

Graphical Abstract

Graphical Abstract


[Research Papers]

Rethinking Air Quality and Climate Change after COVID-19

Joseph Ching, Mizuo Kajino* (*Main member of Aakash)

International Journal of Environmental Research and Public Health


Published: 17 July 2020

DOI: 10.3390/ijerph17145167


[Research Papers]

PM2.5 diminution and haze events over Delhi during the COVID-19 lockdown period: an interplay between the baseline pollution and meteorology

Surendra K. Dhaka, Chetna, Vinay Kumar, Vivek Panwar, A. P. Dimri, Narendra Singh, Prabir K. Patra, Yutaka Matsumi, Masayuki Takigawa, Tomoki Nakayama, Kazuyo Yamaji, Mizuo Kajino, Prakhar Misra & Sachiko Hayashida

Scientific Reports


Published: 10 August 2020

DOI: 10.1038/s41598-020-70179-8


[Research Papers]

Global socio-economic losses and environmental gains from the Coronavirus pandemic

Jacob Fry, Keiichiro Kanemoto



Published: July 9, 2020

DOI: 10.1371/journal.pone.0235654


[Activity Report]

Population density, personal distance and social distancing in the anthroposphere: Implications from the COVID-19 disaster

Manabu D. Yamanaka Senior Researcher, Kozan Osamu Associate Professor, Kaoru Sugihara Specially Appointed Professor

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Since the creation of organisms on the earth, the viruses have been concerning the mutations and evolutions of species, which selected multicellularity, gregariousness, and sociality as humans have. Infection at animal groups has extended viruses' possibility of survival, reproduction and evolution, which results in their coexistence with selected animal species including humans. In particular spatially varying environment with sufficient fresh (river and rain) water around the coastline makes various organisms survive. The coastal regions with biodiversity are suitable for fishery, agriculture and traffic for humans. Not viral but bacterial epidemics forced European to colonize Asian coastal regions and exploited their bioresources. The uneven distribution of human population is essential in the present pandemic, and should be studied also from earth-system and -environmental viewpoints.

We found out that the total cases (a sum of infected, recovered/deceased numbers) of COVID-19 in Japanese 47 prefectures, Indonesian 34 provinces, European 54 countries and US 55 states/territories are principally proportionate to the population density (see Figure), of which the inverse square root corresponds to "mean personal distance" (MPD). For the whole humans over the global land, MPD is (7.7 billion/150 million km2)-1/2 ≈140 m, which is similar to an Indonesian peatland. However, Asian megacities such as Tokyo (12 m) and Jakarta (8 m) have a very short MPD, which is only a few times of so-called social (or physical) distance (1~2 m) for contagious infections. This infection process is similar to aerosol/cloud formation, which should be studied by biometeorology or environmental medicine.

The proportionality factor increases gradually up to ~1 km2 corresponding to an area where everyone would be eventually infected. The value is somewhat larger in Indonesia than in Japan, and seems to be much larger (~102 km2) for the states of US. In Europe smaller countries (< 100,000 km2) are similar to US, while larger countries (Italy, Spain, France, UK, Germany and Russia) are far larger than the common regression line. Variabilities are due to possible evolutions of virus, medical collapse, number of test, shopping area of necessities, and so on. These features are not inconsistent with an important fact that only 20% super-spreaders are responsible for transmission.

The SIR model predicting the infection for closed ('lockdown') people does not concern the spatial size, and its nonlinear governing equations do not yield a simple solution (I + R) for the final number of infected people. This study provides the final size experimentally, and accumulations of similar studies should improve the model and our understanding of pandemic infection processes.

The implications of "social distancing" techniques for sustainability are discussed on the population-area diagram. The risk of megacity due to its broadness without empty spaces should be suppressed by reconstruction of urban functions with a "towner social distance" around 1 km. Otherwise decentralization such as in Tokugawa Japan, which led development of industries and human resources, should be reestablished with the modern computer network. These strategies may contribute to general disaster prevention.

Figure. Total cases (= infected + recovered + deceased) of COVID-19 in (a) Japanese 47 prefectures, (b) Indonesian 34 provinces, (c) US 55 states (+ district = territories) and (d) European 54 countries (classified by WHO) every day during March 18-31 (violet), April 1-30 (blue) and May 1-31 (green), plotted in terms of "mean personal distance" (MPD, defined by the inverse square root of population density) on log-log diagrams. A slant dashed line indicates a -2 power law of MPD (that is, a proportionality to the population density), and shifts upwards/downwards with increasing/decreasing the area where everybody infected.

Keywords:COVID-19, Anthroposphere, Population density, Personal distance, Social distancing, Decentralization


*This article is a reprint of the JpGU-AGU Joint Meeting 2020.


[Activity Report]

How might the unexpected change in air quality caused by the lockdown in India change people’s future behaviour?

Sachiko Hayashida (Aakash Project Leader) and Prakhar Misra (Aakash Project Researcher)
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The Aakash Project commenced on April 1, 2020 at the Research Institute of Humanity and Nature (RIHN) in Kyoto, Japan (https://www.chikyu.ac.jp/rihn_e/project/FS-2019-01.html). The full title of the project is “An Interdisciplinary Study Toward Clean Air, Public Health and Sustainable Agriculture: The Case of Crop Residue Burning in North India”. We chose the name Aakash, which is the Hindi word for sky, because this study addresses the air pollution caused by large-scale post-harvest burning of rice straw in October and November in the states of Punjab and Haryana in northwestern India. This burning causes severe air pollution in the surrounding areas, most notably in the National Capital Region comprising Delhi and its surrounding districts. Some evidence suggests that crop-residue burning negatively affects air quality over the entire Indo-Gangetic Plain (IGP)[1, 2], demonstrating the weaknesses of current policies on regional air quality, which affects the health and well-being of hundreds of millions of people[3].

Before starting the project, we planned to organize the first India–Japan project conference in Delhi at the end of March to promote mutual understanding and collaboration between the Indian and Japanese project members and other stakeholders. However, India was placed on lockdown on March 25 to stop the spread of the coronavirus, and thus we were forced to cancel the conference. Soon after, we heard news reports of clean air in Delhi and other large cities around the world known for their pollution[4,5,6]. It was surprising and rather ironic for us to see the clean air that we were aiming for before we could even start our project.

Inspired by the sudden appearance of clean air, members of Working Group 2 (WG2), whose focus is atmospheric research, held online meetings four times in April and into May to quantify the reduction in the emission of air pollutants in Delhi. From these meetings, we decided to begin a new activity, which we named “Mission DELHIS (Detection of Emission Change of air pollutants: Human Impact Studies)”. This activity aims to quantify the reduction in emissions due to the temporary suspension of anthropogenic pollutant emissions. By comparing the concentrations of air pollutants before and after the lockdown was instituted, it may be possible to accurately quantify anthropogenic emissions. In addition, by estimating non-agricultural anthropogenic emissions, it may be possible to determine the contribution of agricultural burning to the total pollutants emissions. The coronavirus pandemic has presented us with an unexpected opportunity to conduct a social experiment on a large scale.

Lockdown observed from space

Since the 1990s, research and development of new technologies has made it possible to measure air pollutants from space, and today several satellite sensors are used to observe various air pollutants. Among these pollutants, particulate matter (aerosols) and nitrogen dioxide (NO2) are major concerns. The concentration of these pollutants varies according to the degree of emissions from industrial activity, transportation, and daily activities such as cooking; therefore, we can better understand the effects of human activity by monitoring the concentrations of these pollutants. Today, satellite observation not only identifies what is present on the ground, but also reveals what is happening there.

Beijing was once known for its heavily polluted air, and which caused some athletes to withdraw from the 2008 Olympics. As a result of the Chinese government’s various measures against air pollution, the air quality has improved considerably. A satellite sensor, the Ozone Monitoring Instrument, observed a sudden decline in NO2 concentrations over Beijing in August 2008 when the Olympics were held[7]. At present, many countries have instituted urban lockdowns and self-quarantine to slow the spread of the coronavirus. As a result, there have been a series of reports that NO2 concentrations in large cities such as Paris and Wuhan have declined dramatically during the lockdown period[8,9].

The Indian capital of Delhi has been called the world’s most heavily polluted city[10]. However, the skies have turned blue as a result of the sudden lockdown, much to the delight of local residents [11].

We analysed the data obtained by the TROPOMI sensor onboard the European Space Agency satellite Sentinel-5 Precursor TROPOMI(ESA: http://www.tropomi.eu) and found that NO2 clearly decreased after the lockdown was instituted (Figure 1). Because air pollutants emitted from sources such as factories and vehicles are carried by the wind, their concentrations depend on weather conditions, and thus it is inherently difficult to uniquely associate atmospheric pollutant concentrations with their source. However, in the case of NO2, it is relatively easy to identify the source because NO2 has a relatively short atmospheric lifetime and remains close to its emission source; therefore, the difference between the two images in Figure 1 clearly indicates a reduction in emissions.

Figure 1

Figure 1: (left) Mean NO2 concentration March 2–6, 2020 (before the lockdown), and (right) March 30–April 4, 2020 (during the lockdown). NO2 data was taken from TROPOMI (ESA: http://www.tropomi.eu)

At present, the members of WG2 are working tirelessly to quantify the reduction in NO2 emissions. In future research, we will use in situ measurements, satellite data, and model simulations to determine the change in air pollutant concentrations.

Unexpected changes in people’s behaviour

Our original project goal was to “explore ways to change people’s behaviour towards sustainable agriculture in Punjab, and towards clean air and improved health outcomes”. When we proposed this research plan two years ago, the RIHN Research Evaluation Committee doubted the idea that people’s behaviour could be so easily changed. However, the coronavirus pandemic has changed many aspects of people’s behaviour in a very short time. People’s interest in health, especially respiratory system disorders, has increased dramatically, and many people have begun wearing masks. Reports of high mortality from COVID-19 in heavily air-polluted areas [12,13] may also have come as a shock to many Delhi residents.

Clean air in Delhi has been made possible by this temporary lockdown and the resulting halt of economic activity, but air pollution is expected to return to pre-lockdown levels when the lockdown is lifted and economic activity resumes. However, the change in people’s behaviour may not be so easily reversed. People have gradually begun to realize the value of their own health and have become aware of the effects of air pollution and its impact on lung function. The practice of wearing masks in public may become more commonplace. In addition, residents’ experience with clean air and blue skies may have helped them to realize the value of environmental health. How much did the residents of Delhi enjoy having clean air and what did they learn from the experience?

We are currently planning to conduct a questionnaire survey of residents in Delhi and the surrounding rural areas. It is important to obtain data that can be observed only now. We should endeavour to “detect” what people feel at present in addition to the current concentration of pollutants. We must learn as much as possible while we can, so our motto has become “detection, detection, detection”.

(The original version was released on May 25 at Aakash HP: http://aakash.wp.xdomain.jp)


  1. [1] Kaskaoutis, D. G. et al. (2014), Effects of crop residue burning on aerosol properties, plume characteristics, and long-range transport over northern India. Journal of Geophysical Research Atmosphere 119, 5424-5444, doi:10.1002/2013JD021357.
  2. [2] Sarkar, S. et al. (2018), Crop residue burning in Northern India: Increasing threat to greater India, Journal of Geophysical Research: Atmospheres, 123(13), 6920-6934, doi:10.1029/2018jd028428.
  3. [3] Sarkar, S., et al. (2018), Increasing health threat to greater parts of India due to crop residue burning, The Lancet Planetary Health, 2(8), e327-e328, doi:10.1016/s2542-5196(18)30166-9.
  4. [4] Lockdown reduces Delhi pollution; air quality turns 'good' from 'hazardous'-Business Today, March 27, 2020,
  5. [5] Air pollution drops to record low in India following lockdown- Air quality news, March 30, 2020,
  6. [6] Coronavirus: India sees blue skies and clean air as a result of the world’s largest lockdown -The Independent, April 11, 2020,
  7. [7] Beijing Restrictions Reduce Pollution- NASA earth observatory, December 17, 2008,
  8. [8] UCoronavirus lockdown leading to drop in pollution across Europe—ESA, March 27,2020,
  9. [9] Airborne Nitrogen Dioxide Plummets Over China- NASA earth observatory,March 2, 2020,
  10. [10] 2019 WORLD AIR QUALITY REPORT Region & City PM2.5 Ranking, IQAir
  11. [11] India's air quality has improved so much since the country went on coronavirus lockdown citizens can now see the Himalyas for the first time in 30 years-Business Insider Australia, April 14, 2020,
  12. [12] Ogen, Assessing nitrogen dioxide (NO2) levels as a contributing factor to coronavirus (COVID-19) fatality, Science of the Total Environment 726 (2020) 138605,
  13. [13] Wu et al., 2020, medRxiv preprint doi:
    https://doi.org/10.1101/2020.04.05.20054502e (full paper under review).


[Director-General Letter ]2020/05/28

The transition of the COVID-19 under the seasonal change of Kyoto

YASUNARI Tetsuzo, Research Institute of Humanity and Nature

Transition of COVID-19 issue in the world and Japan

It has been almost two months since we started to stay at home and work from home in order to prevent the spread of the new coronavirus infectious disease (COVID-19). The cherry blossom season has already passed, and the azalea flowers are now in full bloom in the fresh green around the quiet Chikyu-ken with few staff members present.

The global COVID-19 pandemic has spread to South America and South Africa, and the data as of May 25 (April 5) shows that the number of infected people is more than 5.4 million (more than 1 million) and the death toll is about 345,000 (more than 50,000). (The numbers in parentheses are based on Yasunari Tsushin as of April 5.) The number of infected and dead people has increased by 5 to 6 times in the last 50 days. In Japan, it has expanded mainly in big cities such as Tokyo and as of May 25 (April 5), the number of infected people is about 17,000 (4,000) and the number of deaths is 839 (93). The number of confirmed COVID-19 cases increased fourfold in the same period, but the number of deaths jumped nearly ninefold . However, as the cases have been decreasing since the beginning of Golden Week holidays in May as shown in Figure 1, the declaration of a state of emergency issued by the government on April 7 has been lifted (for the time being).

Transition of COVID-19 issue in Kyoto

Now, with regard to the situation in Kyoto (including Kyoto City and Kyoto Prefecture), as shown in Figure 2, since a cluster (group of infected people) from university students who returned from a graduation trip in Europe was confirmed on March 29, the number of infected people has soared, and due to the outbreak of a group infection at one hospital in the city, the number of cases reached nearly 20 a day on April 3, and there was growing concern about an explosive increase called "overshoot" just like what happened in Europe and America. Fortunately, the number of cases has been declining since mid-April. Only a few cases have been confirmed since Golden Week, and zero cases since May 15.

Why has it started to decline in Kyoto since mid-April? The government declared a state of emergency on April 7th, and Kyoto was not even included at that time. The effect of an emergency declaration cannot have appeared immediately. Several factors may have worked synergistically. First, the formation of group clusters by students had a great impact on Kyoto Prefecture and Kyoto City, and the governor and the mayor held an urgent joint press conference on April 2nd to urge the citizens to refrain from going out unnecessarily, sightseeing in Kyoto, and refrain from coming and going (including commuting to work and school) in the Kansai area where the number of infections is increasing rapidly in addition to maintaining a social distance. The cherry blossoms were in full bloom at the beginning of April this year, and there would have been so many people gathering at the famous Sakura spots in Kyoto city and Kyoto prefecture if it were not for the request for self-restraint, which seems to have been highly effective. The other fortunate factor was that a large number of foreign tourists who would rush to Kyoto to see the cherry blossoms at this time of year could not make their trips due to COVID-19 problems this year. Photo 1 is a picture the cherry blossoms in full bloom taken at the Kamogawa (Kamo-River) on April 3, but you can see that there are few people along the river. This virus is said to develop within 1-2 weeks after infection. It seems that infections caused by the first student cluster and hospital cluster in Kyoto prefecture have been effectively suppressed since the joint emergency declaration by the Governor and Mayor of Kyoto in early April, and the results seemed to have appeared in the middle of April. The declaration of a state of emergency nationwide issued afterward may have had a certain effect in suppressing the movement of people from other prefectures as well.

In Kyoto, where a large number of tourists usually come visit every year, it seems that stay-at-home requests, which came into effect from the end of April to Golden Week, were quite effective to reduce the number of cases. During this Golden Week, I looked into the Kiyamachi and Pontocho neighborhoods where a crowd of people can be seen every year, but this year all the restaurants were closed and almost no one was walking. Photo 2 is taken at Kamogawa near Shijo Ohashi on the evening of the last day of Golden Week, May 6th. Every year, restaurants along Kamogawa start opening a river bed (Yuka) in May, and the lively night view would spread, but it looked like a night view of a ghost town that day. All the shrines and temples that are tourist attractions in the city were also voluntarily closed. Photo 3 is a full view of Kiyomizu-dera Temple taken on Sunday, May 10, but there is no sign of people on the stage of Kiyomizu. Since May 15, about two weeks after the Golden Week, the days with zero cases have been achieved in Kyoto due to the stay-home effect. Ayu (Sweetfish) were released in Kamogawa to signal the beginning of summer, and ropes to keep away Japanese cormorants (Phalacrocorax carbo ) were also stretched near Shijo Ohashi (Big Bridge) (Photo 4). The number of people who enjoy dining and drinking on the Yuka along the Kamogawa river has gradually increased, and the town of Kyoto seems to have finally regained its season.


Number of COVID-19 infected people in Japan (as of May 28)

Number of COVID-19 infected people in Kyoto Prefecture (as of May 28)

Importance of local/regional level democracy for the COVID-19 issue

On the other hand, stay-at-home and business suspension requests have significantly reduced the income of so many shops and businesses. Requests for business suspension should be carried out in combination with compensation, but the government's response to this issue is so slow that they have only started to put it into practice little by little by the strong demands from many local governments. Nevertheless, the reason why the request for voluntary stay-home and business suspension could be carried out quite effectively was probably because there was sharing of problems based on the good relationship of trust between local governments of Kyoto Prefecture /Kyoto City and citizens. The positive cooperation of hotels in the city to prevent overwhelming hospitals was also effective. Similar effects have been seen in Tokyo and Osaka as well. In some European countries, mandatory lockdowns were carried out accompanied by penalties, but they couldn’t stop hospitals from being overwhelmed, causing an explosive increase in infections and deaths. Japan's considerable control over the spread of infection, at least at this point, strongly suggests that democratic policies and actions at the local/regional level are more important than the enactment of such legislation.

(Acknowledgment: I am grateful to Ms. Megumi Arita for completing the English version of this message.)

  • Photo1Photo 1: Full blossom of cherry trees along Kamo river at Shimogamo (Apriol 3) (left) left bank near Izumoji-bashi, (right) right bank near Aoi-bashi.

  • Photo2

    Photo 2: Evening scenery near Shijo Ohashi (Bridge) at Kamo river (May 6). The lights of most of buildings were off.

  • Photo3

    Photo 3: Whole view of Kiyomizu-dera temple from Amidagamine, Higashiyama (May 10). No tourists were seen at the famous Butai (Stage) of the temple.

  • Photo4

    Photo 4: Upstream view of Kamo-river from Matsubara-bashi (May 21). Ropes to keep away Kawa-wu (cormorants) were also stretched across the river sides.


[Activity Report]

COVID-19 affects social activities in Indonesia

Nina Yulianti, Kitso Kusin (Univ. Palangka Raya), Masafumi Ohashi (Kagoshima Univ.), Masahiro Kawasaki,
Manabu D. Yamanaka, Osamu Kozan (Res. Inst. Humanity & Nature) and Daisuke Naito (Kyoto Univ.)

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The nitrogen dioxide (NO2) pollution over a region is linked to traffic, industrial and agricultural activities since NO2 is released by power plants, industrial facilities, motor vehicles and biomass burning. The column density of NO2 measured by a satellite is a first-level indicator of resident activity in the region. For example, recent Tropomi instrument on board the Copernicus Sentinel-5P satellite has shown a decline of air pollution over northern Italy and Chine coinciding with its nationwide lockdown to prevent the spread of the Coronavirus disease 2019 (COVID-19). The spread led to the dramatic reduction in NO2 concentrations in all major cities of China between late-January and February 2020. The NO2 drop in late-January is visible on images of the satellite site, coinciding with the nationwide quarantine.[1]

About the pollution map, GOME-2/SCIAMACHY DOAS nadir data browser shows the reduction of NO2 concentrations over China and Indonesia between December 2019 and May 2020 in Fig. 1. The OMI/Aura/NASA data of Indonesia are summarized in Table 1 for the heavily polluted Jakarta and less polluted Riau of Sumatra. In Greater Jakarta, the drop in absolute amounts is not so clear due to the seasonal variation. When the seasonal variation is cancelled, NO2 was reduced to 60% of the average value of 2014 − 2019. The NO2 drop is also seen in the imageries of CREA, Fig. 2, which show the NO2 levels of March 12 − May 5 of 2020 and 2019.

Figure 1

Fig. 1 Nitrogen dioxide NO2 change observed by GOME-2/SCIAMACHY DOAS nadir before and after COVID-19 in Jakarta and Beijin: December 9, 2019 and May 3, 2020
Note the orange areas over Jakarta and north China in the left picture turned to faint color in the right picture.

The nation-wide total number of the COVID-19 cases stood 36,406 on June 12, 2020. [2] In Greater Jakarta the total number was 8,355 or 25% of the nation-wide cases. Positive cases were reported in early-March 2020. Since then, the daily number has increased from 113 on April 2 to 1,111 on June 12.

Google reported Jakarta people’s visits and length of stay at work and residential places change compared to a baseline that is a median value during the 5-week period Jan 3–Feb 6, 2020.[3] Google has calculated these changes using the same kind of aggregated and anonymized data used to show popular times for places in Google Maps. The mobility data at workplace starts decreasing in early-March reaching 53% in late-May while that in residential increases up to 124%. In Riau province of Sumatra, the total number of cases is low, 120 (0.4% of nation-wide) on June 13. The NO2 column density does not drop, suggesting almost no effect of COVID-19 on traffics, industry and people’s activity. Google reported Riau people’s mobility change at workplace reaching 75% and in residential increasing to 112% in late May. These mobility changes are smaller than those of Jakarta. Note that these social data also depend on Ramadan for April 23 − May 23, 2020.

Figure 2

Fig. 2 Nitrogen dioxide NO2 levels of Greater Jakarta and Banten region: March 12 to May 5 (left) 2020 and (right) 2019,

Indonesian society consists of some number of large cities and a numerous number of small villages. We have investigated how COVID-19 affects those different types of local societies using the SIR numeric model.[4] This basic mathematical model is simply described by three differential equations.

N = S(t) + I(t) + R(t),

dS(t) / dt = − βI(t)S(t),

dI(t) / dt = βI(t)S(t) − γI(t),

dR(t) / dt = γI(t),

where N is total population, t time delay after the first patient, I(t) number of infectious, S(t) susceptible, R(t) recovery including removed, β an infection rate constant, and γ a recovery rate constant from infection. For these equations, a basic reproduction number, R0, is a measure of infection strength, which is given by:

R0 = Nβ / γ.

Table 1. Tropospheric column density of NO2 before and after COVID-19
column density in units of 1015 /cm2
Month of 2020 Jakarta, Java Riau, Sumatra
January 3.4 0.5
February 2.2 0.7
March 2.5 0.7
April 1.9 1.0
May 2.3 1.1
Data from OMI/Aura/NASA, https://disc.gsfc.nasa.gov/datasets?keywords=OMI&page=1
Note 1: The first COVID-19 case was reported in early-March.
Note 2 The average value of NO2 in South Asia 2020 is estimated to be 2× 1015 /cm2
after Ul-Haq et al. Zia ul-Haq, Salman Tariq, Muhammad Ali, Advances in Meteorology, 2015,
Article ID 959284, http://dx.doi.org/10.1155/2015/959284

According to the reported epidemiological statistics of China, Europe and Japan, R0 are presently (March 2020) estimated to be 5, 2-3 and 1.5, respectively.[5] This number can be reduced to R by an efficacy factor of (1 – c) that depends on lifestyle habits including social communication and distancing, washing hands, masks etc.,

R = R0(1 − c).

With proper prevention of epidemic, R of Japan was reduced to 1.06. Based on information about China, Europe and Japan, we assume in the present calculation that a) day of double infection is 10 days, b) γ is around 0.055 day-1 to calculate I(t) as a function of population, N = 5,000 for a village community and 1,000,000 for a megacity. Although small population density in village makes social distancing large, in the following calculation we assume that human relationship among people of the village community under closed circumstances is much closer than in the city, resulting in a larger (1 – c) value. For simplicity purpose, using a doubled R value for village as shown in Table 2, we numerically calculate epidemic curves in Fig. 3. The number of cases in village peaks on 6th day while 45th for city. Almost all residents in the village suffer from COVID-19 within two weeks while less than a half of people are infected in the city with a seven times slower infection speed. People in city have time to prepare against pandemic while village people do not. Since the local community of the village gets easily collapsed with chaos spread among residents, a small society should take very quick prevention against epidemic to save its community.

Table 2. Results of epidemic curves of a model calculation for village and citya)
 PopulationAreaSDb)ReproductionInfectious function, I(t)
 N(km2)(m)number, Rmaxday of maxtotal (T)T/N (%)
a) day of double infection = 10 day corresponding = 0.07 day-1: day of half-recovery = 12 day corresponding γ = 0.055 day-1
b) Social Distance ~ (population density)‒1/2 = (Area/N)1/2


  1. https://www.esa.int/Applications/Observing_the_Earth/Copernicus/Sentinel-5P/COVID-19_nitrogen_dioxide_over_China, Fan, C.; Li, Y.; Guang, J.; Li, Z.; Elnashar, A.; Allam, M.; de Leeuw, G. The Impact of the Control Measures during the COVID-19 Outbreak on Air Pollution in China. Remote Sens.2020, 12, art.#1613.
  2. https://covid19.go.id/peta-sebaran
  3. Google LLC "Google COVID-19 Community Mobility Reports". https://www.google.com/covid19/mobility/
  4. W. O. Kermack and A. G. McKendrick, Proc. Roy. Soc. (London) A, 115, 700 (1927), doi:10.1098/rspa.1927.011).
  5. References for basic reproduction numbers, R0 and R: S. Kado of Kyoto University, https://bit.ly/RADIT21KD20200327, Y. Liu, A. A. Gayle, A. Wilder-Smith, J. Rocklöv, J. Travel Medicine, 27(2), 2020, taaa021, https://doi.org/10.1093/jtm/taaa021, H. Okumura of Mi’e University, https://oku.edu.mie-u.ac.jp/~okumura/python/COVID-19.html
Figure 3

Fig. 3 Calculated epidemic curves in logarithmic scale for (left) small village N = 5,000 / R = 2.52, and (right) megacity N = 1,000,000 / R = 1.26 as a function of day after first case. See Table 2 for epidemic parameters.


[Activity Report]

Clean Air and Imagined Sustainability: The case of India
What does clean air on account of Covid-19 virus induced lockdown hold for environmental sustainability in India?

Prakhar Misra, Research Institute of Humanity and Nature
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Figure 1

Figure 1 Himalayan Dhaualadhar range from a distance of about 200km at Jalandhar, Punjab, India. It was said to be seen for the first time in 30 years.
Picture credits from Twitter user @Deewalia

As of April 19, 2020 Covid-19 pandemic has resulted in more than hundred-fifty thousand deaths and about 2.2 million people infections [1]. To suppress the spread of virus, more than 40 countries have enforced mandatory quarantines (popularly referred to as “lockdown”) or non-mandatory recommendations of quarantine, social distancing, closure of certain businesses and gatherings [2]. During a lockdown, a partial or complete suspension of non-emergency services takes place. This suspension of non-emergency services, which include various polluting sources, has produced an unexpected withdrawal of emissions into environment. At the same time, the public in many polluted cities is experiencing cleaner air quality days. This implies that a third of the global population is experiencing restrictions but also seeing cleaner air. As a researcher of human-environment interaction pertaining to air quality, I am interested in how this co-occurrence may change public perception of environmental sustainability in severely polluted countries like India. The answer to this question would be immensely important for promoting people’s behavioural change and policies that incorporate environmental sustainability. Although survey-based studies would better answer this question, we would like to offer our view based on a compilation from popular news articles. This letter aims to offer some glimpses into how the coronavirus induced lockdown and clean air are shaping public’s imagined sustainability.

Clean air and changed lifestyle during lockdown

Figure 2

Figure 2 Decrease in air quality index pre-lockdown (March 22) and during lockdown (March 29) in Indian cities. Reproduced from [3].

National lockdown was initiated on 24 March, 2020 in India. The lockdown approach was first applied in mid-January in China’s Wuhan province to enforce “socialdistancing” for reducing coronavirus spread. After little over a month into the lockdown, first reports emerged about a visible decrease in nitrogen dioxide over Wuhan, which was observed from European Space Agency’s TROPOMI sensor. Similarly, a week into the lockdown in India, various observations emerged on probable air quality improvement due to lockdown of transport and industries. In cities like New Delhi, people started sharing their experience of consecutive blue skies on social media. Some news reports quantifying the reduction in fine particulate matter (PM2.5) in both pre and post lockdown periods from various corners of the country also began to appear. These reports showed a decrease of 20%-50% in cities, most notably for cities in Indo-Gangetic plains. In addition, the public imagination was captured when an interesting observation made in Jalandhar city, Punjab, showed up. Over there, previously hidden Himalayan Dhauladhar range could now be seen for the first time in 30 years. This “blue sky experience” has convinced the public that lockdown resulted in clean skies in Indian cities.

At the same time, there are indications that adaptations to the pandemic at the level of daily lifestyle may translate to future behavioural change. For instance, masks are not commonly worn by Indian public possibly due to the feeling of social awkwardness and claustrophobia associated with them [6]. Even during extreme air pollution episodes, wearing a mask is limited to only those who are gravely conscious of the effects of pollutants. Currently as masks have emerged as an important tool for self-defence against the virus spread, there is now a wider adoption of wearing masks. People are strongly encouraged to wear masks with some municipalities even punishing those who are not wearing them [7]. Lockdown’s economic costs are being paid for by the government, industries and the general populace, including those people who are outside the social security net. Some industries are adopting telework to survive the lockdown-induced employment loss. It is becoming clear to them that teleworking would save costs for renting office space , air-conditioning, etc. and allow mothers to be part of the workforce. Similarly, the Indian government has expanded the features of National Agricultural Market web-platform (e-NAM) as a response to the rural lockdown. It now allows remote bidding, and e-payment for farmers’ produce so that the farmers do not need to physically visit market or banks. These decisions are not only helping in surviving through the coronavirus but they are also beneficial for air quality as they lead to a lower travel and energy related emissions of pollutants.

How long will it sustain?

However, questions loom regarding the efficacy of lockdown in cleaning the environment. It has been pointed out that the optimum level of emission from the traffic cannot and should not be considered as zero since trucks supplying essential food supplies, medical vehicles as well as law and order vehicles are plying through the city. Residential emissions from biomass-fuel combustion, large contributor to urban air pollution, remain active and it is unlikely that the lockdown would significantly reduce them. The lack of enforcement of environmental management regulatory protocols during the lockdown might give industries Figure 2 Decrease in air quality index pre-lockdown (March 22) and during lockdown (March 29) in Indian cities. Reproduced from [3]. like steel and mining a free hand to pollute without any watchdog. Furthermore, as the fossil fuel industry is the only industry that can provide energy and materials that are needed immediately, environmental regulations are being relaxed in US [4] and China [5] to restart economic growth. Thus, any gains in clean air on account of low emissions are to be short-lived.

Social responses to the policy interventions during the virus spread potentially point to the need for a more serious embracing of a broader idea of sustainability. In 1983, Benedict Anderson came up with the notion of “imagined community”, in which any large community could be “imagined” by the people who perceive themselves as part of that group. The concept can be invoked to describe the emergence of an “imagined sustainability”, within which people share a mainstream perception of sustainability without necessarily realizing it. According to this perception economic growth always adversely affects environmental health. This was evident during the clean air episodes when social environmentalists urged the government to heed this “wake-up call” to stop “obsession” with “(economic) development at the cost of environment”. This is an imagined sustainability invoked specifically by the virus spread. Such an interpretation can be naïve, and does not serve well for a full sharing of a sense of sustainability beyond the short-term behavioural change. We need a wider appreciation and elaboration of a variety of eco-economic decoupling strategies, including the one that promotes economic growth without corresponding increase in environmental pressures. These strategies often incorporate environmental accounting into economic growth. Concepts, such as quality of living, green growth and inclusive wealth are examples of such strategies.

The current clean air is unequivocally incidental to policy enabled national lockdown. However, it has offered two encounters which may have a bearing on subsequent public perception. First, the short “blue sky experience” may offer a vision for future policies to adopt technologies which decouple economic growth and air pollution. Second, the temporary public behavioural change may lead to greater concern for public health. The strong willpower of governance and public engagement is clearly being demonstrated during the current national lockdown in India. It remains to be seen how the same willpower can be exercised to invest in green growth. In a recent op-ed [8], the former President of Indian Academy of Science made an apt summary in context of India’s war on Covid-19 which remains true for environmental sustainability as well: we need “detection, protection, prevention, prescription and, last but not least, … participation”.

-- Postscript--
As a technical note we may add that concentrations of pollutant are determined not only by the emission but the also the dynamics of regional meteorology. Quantifying the role of the lockdown in air quality improvement is scientifically a challenging question. Currently our team at Aakash is investigating this using our original surface data from PM2.5 monitors installed in Delhi and satellite datasets.

References from news reports:

  1. [1] Coronavirus disease 2019 (COVID-19) Situation Report – 90
  2. [2] A third of the global population is on coronavirus lockdown — here's our constantly updated list of countries and restrictions
  3. [3] Six days into the lockdown, here’s how much air quality has improved in major Indian cities,
  4. [4] E.P.A., Citing Coronavirus, Drastically Relaxes Rules for Polluters - The New York Times,
  5. [5] Political decisions, economic realities: The underlying operating cashflows of coal power during COVID-19
  6. [6] Delhi is engulfed by toxic pollution. Why isn’t anyone wearing masks?
  7. [7] Coronavirus: Now, you will be punished if you don't wear mask in Mumbai
  8. [8] Update on India’s war against COVID-19