Delhi's air back in 'severe' zone as smoke, slow winds trap pollutants

Delhi’s air quality index (AQI) dropped into the deep red “severe” zone yet again on Wednesday, primarily due to the heavy influx of smoke from stubble fires, which was worsened by slow winds, dipping temperatures and remnants of firecracker emissions, ensuring that the city’s pollution crisis persists and residents remain trapped in a hazy mist.

- Snehil Sinha and Jasjeev Gandhiok

Another 'severe' day in Delhi as farm fires lengthen bad air spell

The Capital’s AQI on Wednesday clocked 401, according to the Central Pollution Control Board’s (CPCB) 4pm bulletin, marginally worse than 397 (very poor) a day ago, and the first severe reading since November 9.

The surge in pollution follows an upswing in the number of stubble fires in upwind Punjab over the past few days. Satellite data recorded 2,544 farm fires across the state on Wednesday, significantly more than 1,776 a day ago, and 1,624 on Monday.

Northwesterly winds, blowing into Delhi from Punjab, have over the past few days carried plumes of smoke from these burning paddy fields and settled these pollutants in the Capital’s air, capping the city’s turnaround after two-and-a-half days of relatively clean air.

A sharp spell of rain last Thursday night and Friday morning wiped Delhi’s air of pollution and dragged it out of a spell of seven days of severe air in nine days. The air quality improved till Sunday (Diwali day) afternoon, when the AQI settled at 218.