Firecrackers caused over 80% of Delhi’s pollution on Monday

Firecrackers caused more than 80% of Delhi’s pollution on Monday, according to models from the Indian Institute of Tropical Meteorology.

Delhi’s air had already worsened during Diwali, when its average air quality index reached 376, the highest for the festival in five years.

The city remained in the very poor category on Monday, with smog and some monitoring stations recording severe air quality.

The air quality index briefly improved to 299 on Tuesday afternoon, but rose to 302 by 6pm, putting it back in the very poor category.

Firecracker pollution lingered: it accounted for 29.9% of pollution from 1am to 9am on Tuesday, while secondary organic compounds accounted for 17.5%.

Favourable winds helped disperse pollution, and crop-residue smoke from neighbouring states was not a major contributor on Monday despite farm fires in Punjab.

Delhi’s air will depend on winds and continuing emissions from routine sources.