An Interdisciplinary Study Toward Clean Air, Public Health and Sustainable Agriculture: The Case of Crop Residue Burning in North India
This study addresses air pollution caused by annual large-scale post-harvest burning of rice-straw in October and November in the states of Punjab and Haryana in Northwest India (Fig. 1).The burning causes severe air pollution in the surrounding areas, most notably in the Delhi-National Capital Region.Some evidence suggests that crop-residue burning negatively affects air quality over the entire Indo-Gangetic Plain (IGP), demonstrating the potential negative impact of changing agricultural practices on regional air quality on the health and well-being of hundreds of millions of people.
Historically, the Indian Punjab region, a semi-arid zone with low precipitation, was not suitable for intensive cultivation.Traditional agriculture in the region consisted of a combination of cultivating wheat and raising livestock (cattle). The development of irrigation canals during the British colonial period transformed the region into a granary. In the 1960s, the area became the seat of the so-called “Green Revolution” and played a central role in producing food for the populous nation.In the 1970s, most of the region adopted a double-cropping system of wheat and rice. However, this cultivation practice required farmers to sow wheat seeds immediately after the rice harvest. While traditional hand-harvest allowed the cropping of rice stalks near ground-level, the recent increased use by harvesters has left large quantities of stubble in the fields.Farmers are therefore forced to quickly burn this crop residue (stubble and stalk) in order to prepare for wheat seeding in the short period between late October and early November. Winds in this season shift to the northwest, often blowing smoke from stubble burning to Delhi-NCR, markedly affecting air quality there. Yet, the cause-and-effect relationship between stubble burning in the Punjab region and worsening air pollution in Delhi has not yet been established quantitatively. This lack of definitive quantitative evaluation is principally due to the poor state of the air pollution monitoring network in the region.Unfortunately, many farmers of the Punjab region are reluctant to acknowledge their own actions as the cause of air pollution in Delhi, and there is also some disagreement among academic researchers as well.
Project structure & research plan
This project utilizes observational data and model simulations in order to provide a scientific examination of the connection between stubble burning in Punjab and severe air pollution in Delhi. Based on this scientific understanding, we will pursue a pathway of social transformation toward clean air, public health and sustainable agriculture. We will organize three working groups to approach stakeholders; all working groups will examine various measures to raise awareness regarding farmer/community behavior relevant to air pollution as well as that of other stakeholders and government.
Questionnaire survey in all districts in the state of Punjab
We carried out a questionnaire survey in all 22 districts of the state of Punjab under a contract with the Center for International Projects Trust (CIPT), a non-profit organization in India. Two villages per district and 50 households per village were selected, representing a total of 2,200 households. Surveys gathered information on household financial status, agricultural practices, health awareness, and so on. Even in the midst of the spread of COVID-19, the CIPT was able to carry out surveys of all 2,200 households in FY2020. The questionnaire also included information on rice stubble burning. Because individual farmers may fear punishment for certain agricultural practices, in order to gain further information, we also conducted direct interviews with village representatives and found difference between the northern part and the southern part of the Punjab state. In addition, an increase in the burnt area in the south part was found after the COVID-19 pandemic, suggesting its impact on labour availability and cultivation period.
Some simulations of air pollutants revealed that the emission inventories from straw burning developed in western countries are underestimated. To reduce pollutant emissions from straw burning, we developed bottom-up inventories The optimal one is shown in Fig. 2 as the activity data (the amount of straw burnt in the fields).
RIHN/Japan Agency for Marine-Earth Science and Technology
SUDO Shigeto(Institute for Agro-Environmental Sciences, The National Agriculture and Food Research Organization)
Researchers at RIHN
YASUTOMI Natsuko(Assistant Professor)
ARAKI Hikaru(Research Associate)
ASADA Haruhisa(Nara Women’s University)
UEDA Kayo(Hokkaido University)
KAJINO Mizuo(Meteorological Research Institute)
INUBUSHI Kazuyuki(Tokyo University of Agriculture)
MATSUMI Yutaka(Nagoya University)
Evaluation by an external evaluation committee