Delhi’s air quality index was in the “very poor” category on Saturday, according to the Central Pollution Control Board. However, firecrackers burst on Diwali, despite a ban on sale, may worsen air quality and take the AQI to the “severe category” by evening, PTI reported, citing weather experts.

At 12 pm, Delhi’s overall AQI was 378. By 1 pm, the AQI in Delhi’s Anand Vihar area was already in the “severe category” at 440. In Gurugram too, the AQI was in the “very poor” category. The reading in Noida’s Sector-1 was 394, which also falls in the “very poor” category.

The Ministry of Earth Sciences’ air quality monitor, SAFAR, said that the concentration of PM 2.5 in Delhi on Diwali could be the lowest in the last four years if no firecrackers are burnt.

Kuldeep Srivastava, the head of the Indian Meteorological Department’s regional forecasting centre, told PTI that the air quality was likely to improve after Diwali due to an increase in the wind speed.

Earlier this week, the National Green Tribunal had imposed a blanket ban on the sale of firecrackers in Delhi and the National Capital Region till November 30.

Gurugram also imposed a complete ban on firecrackers, three days after the Haryana government permitted their sale and use for two hours on festivals such as Diwali, citing impact on small traders.

Delhi’s air pollution typically worsens in October and November due to farmers burning stubble in neighbouring states, unfavourable wind speed and local emission of traffic fumes in the city. Firecrackers ignited for Diwali add to the problem.