Agricultural residue burning in India: health impacts and mitigation alternatives

Degraded air quality shortens the lives of millions in India, where the burning of crop residue is an important contributor to air pollution and public health burden. Despite government bans, fines and subsidies for no-burn practices, agricultural fires remain widespread. This paper aims to help inform alternative interventions to crop residue burning that are both straightforward to implement and attractive to the farmers community while mitigating health impacts. Unlike traditional studies of Indian air pollution which start by assuming an intervention, such as removing the entire emissions from a source, and then calculating its effects, we used inverse modeling to start from the air quality effects of agricultural fires and then quantify the potential benefit of actions at district- and hourly level. Instead of focusing on a single hot spot such as Delhi, where air quality problems have been notoriously serious, we focus on the whole Indian population - since impacts of air pollution are not limited to one location and epidemiological evidence shows no threshold of PM2.5 under which no harm to humans is observed.  From 2003 to 2019, we find that Indian agricultural residue burning caused an annual average of 69,000 PM2.5 exposure-related premature deaths, of which Punjab, Haryana, and Uttar Pradesh states contribute 67–90%. These health impacts, valued at 23 billion USD annually, are equivalent to 38% of the total health expenditure, or 7.8% of the gross value added from agricultural activity in India. Over 17 years, these two ratios have increased from 29% to 40%, and from 6.1% to 9.2%. The average air quality impacts attributable to agricultural fires is 2.4% lower in drought years, 4.8% higher in flood years, and close to 17-year average in years with normal rainfall. We show that six districts are responsible for 40% of annual burning-related air quality impacts in India. Burning a few hours earlier during the day could also avert a significant number of premature deaths each year. Our findings support the use of targeted and potentially low-cost interventions to mitigate crop residue burning in India, motivating further research regarding cost-effectiveness and feasibility.