Air pollution in parts of Delhi entered the “severe” category on Monday, while the city recorded an overall air quality index in the “very poor” category for the third consecutive day.

Monitoring stations at three places in Delhi – Mundka (422), Wazirpur (419) and Rohini (418) – registered air quality in the “severe” category at 6 pm on Monday, according to data on the Central Pollution Control Board’s website.

An air quality index ranging between 401 and 500 falls under the “severe” category. A reading of above 400 can affect healthy people and seriously impact those with existing illnesses.

The National Capital’s 24-hour average air quality index at 4 pm was recorded at 347, according to the Central Pollution Control Board’s bulletin. An air quality index ranging between 301 and 400 falls under the “very poor” category. Air quality in the “very poor” category can lead to respiratory illness on prolonged exposure.

On Sunday, Delhi Environment Minister Gopal Rai said that although the number of crop burning incidents in Punjab has reduced, emissions from vehicles have become an important reason for air pollution in the capital, PTI reported. He urged the Centre to strictly ban buses running on poor-quality diesel in the National Capital Region.

Air quality plunges in the winter months in Delhi, which is often ranked the world’s most polluted capital. Stubble burning in Punjab and Haryana, along with falling temperatures, low wind speed and emissions from industries and coal-fired plants contribute to air pollution in the region.

On Monday, however, the Union Environment Ministry said that the total stubble burning incidents in northern India around Delhi fell by 54.2% as compared to last year, and by 44.3% as compared to 2021 from September 15 to October 29. The figures pertained to Haryana, Punjab, Delhi, as well as parts of the National Capital Region that fall in Uttar Pradesh and Rajasthan.

The ministry said that Punjab recorded 5,254 such incidents, as against 12,112 last year. Haryana witnessed 1,094 incidents as compared to 1,813 last year.