Delhi: This October dirtier than last year, but second cleanest since 2015

NEW DELHI: This October was a little dirtier compared with last year. The average Air Quality Index (AQI) of October 2022 was 209 as against 173 last year, data of Central Pollution Control Board has shown.
The first half of October 2022 was relatively cleaner with two "good-air" days, but the air quality severely deteriorated in the second half of the month as winter conditions started setting in. Experts said increased cases of stubble burning, low temperatures and calm winds affected the air quality.
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Though this October was worse than last year, it was still the second cleanest since 2015 when CPCB started measuring AQI. While this October saw two "good-air" days, October 2021 witnessed just one such day. However, no "good-air" day was recorded in October from 2015 to 2020.
While there were seven "very poor" days this October, no such day was recorded in the same month last year. Between October 1 and 15 this year, there was only one "poor" day as the air quality hovered mostly in the "satisfactory" category. However, there was a significant rise in pollution levels in the second half of the month.

VK Soni, head, environment and research centre, India Meteorological Department, said, "There were only a single spell of rain from October 7 to 12 this year, while there were five rain spells in October 2021, which was the cleanest since 2015 as rain helped in settling down pollutants."
"In contrast with October 2021, this year increased cases of stubble burning were reported in the month. Even low temperatures affected the dispersion of pollutants. The average maximum and minimum temperatures in October 2022 were 31.5 and 18.7 degrees Celsius. However, mean monthly maximum and minimum temperatures last year were 33 degrees and 20.5 degrees Celsius. Besides, Diwali was observed in October this time," added Soni.
Anumita Roychowdhury, executive director, research and advocacy, Centre for Science and Environment, said, "Last year, Diwali was in early November and the prolonged rain during October also pushed most of the stubble burning to early November. But this year, after rain in the first half of October, farm fires picked up in the second half coinciding with Diwali as well as development of inversion conditions."