Is Agri-residue Burning a Menace for Air Quality & Public Health in Delhi, India?

Skies over Delhi become blurred and visibility is significantly reduced and the air is hefty and causes a burning sensation in the eyes. As every year in November, a thick blanket of smog veils Delhi and its surrounding National Capital Region-NCR of India, which constitute the world’s most polluted megacity. According to a senior pulmonologist and member of the WHO commission on global air pollution and health, patients experiencing breathing problems increase by 30-40 percent every year during October-November. But Delhi’s smog wasn’t always this bad in early winter; it started only about 10-15 years ago. Satellite images show high Aerosol Optical Depth (AOD), as soon as farmers start burning paddy straw and stubble (agri-residue) in agricultural fields, and air quality severely deteriorates. The agri-residue smoke from agricultural areas surrounding Delhi, combined with urban pollution from vehicles, industry, and fireworks from the Diwali festival, increase pollutants to the severe category. Smoke from farm fires after harvest contributed about ⁓ 26-50% of the PM2.5 (tiny particles that damage lungs and can worsen cardiac ailments) to Delhi’s air in November 2023. The average resident of this megacity is on track to lose ⁓ 8 years of life expectancy if high pollution levels persist (EPIC, 2023). Authorities in this smog-ridden capital, even imposed emergency school closures of 7 to 15 days in 2016, 2017 and 2023 to mitigate health issues in the population, who flooded emergency wards at hospitals.