An Intriguing Connection between Crop Production, Residue Fires, and Air Quality over Northern India Inferred from NASA's A-Train Satellites and Ground Observations

The practice of agricultural waste burning over northwestern India and resulting haze over the region during the post-monsoon season have received widespread attention among the scientific community and also well-covered by the international media. The severe haze event of the 2016 post-monsoon over northern India observed record-breaking levels of particulate matter pollution measured from satellites and ground sensors. In parallel, New Delhi-the capital city of India, and other cities in the populous Indo-Gangetic Plain (IGP) have been consistently ranked among the most polluted cities in the world according to the recent WHO reports. In the present work, we explore a likely connection between crop production amounts, the density of residue fires, and resulting aerosol loading using a long-term record of satellite observations from NASA’s A-train sensors in conjunction with the ground-levels readings of PM2.5. We find that rising levels of air pollution strongly correlate to the concurrent and steady increase in the crop production amounts and fire counts. We further investigate the possibility to predict the total number of fires and thus the levels of air pollution before the onset of burning season based on the well-defined triangular relationships between the crop amounts-NDVI-fire counts. Such predictions can serve as a guideline for the air quality related planning and preparedness. Rising levels of crop fires and deteriorating air quality over IGP is a serious concern demanding urgent remediation policies as it affects the health of millions living in one of the most densely populated regions of the world.