Good news for Delhi: pollution levels are reduced, and the winter season is starting on a cleaner note.
PM 2.5 levels begin to exceed 24-hour mark when monsoon retreats, resulting in dry air days. This period began in September 2018 and 2020, and was postponed to October 2019 and 2021. According to a study by the Centre for Science and Environment (CSE), meteorological conditions resulting in an extended period of rain this year have led to a cleaner threshold for the 2021 winter than in previous years.When the monsoon retreats, PM 2.5 levels begin to exceed the 24-hour mark, resulting in dry air days.This period began in September 2018 and 2020, and was postponed to October 2019 and 2021.The time frame is considered to be pre-winter in the analysis. The intensive monsoon and delayed rainfall this year, according to Anumita Roychowdhury, executive director, research and advocacy at CSE, resulted in a much more productive pre-winter season this year.The weather is influencing what we are seeing today.The fire count is lower, but it could also be due to the rains that are halting the fires.We can't predict how much air pollution will rebound this winter. This year, the fire count in the pre-winter season is less than half of what was recorded last year.This may be due to the rain spells that we saw this year or cloud cover, which may have hampered satellite imagery.The fire count for the pre-winter season was 5,078, versus 2,351 this year (as reported by Punjab and Haryana).It stood at 2,299 feet in 2019, up from 1,765 feet in 2018. The contribution of farm stubble burning to air quality started around October 10, 2021, the same as in 2018 and 2020.This contribution reached its peak on October 16, when 14% of PM 2.5 levels in Delhi was attributed to stubble burning by the SAFAR monitoring system.The contribution of stubble burning to PM 2.5 levels can rise to 40%.Last year, the average contribution per day was 12.2%, up from 8.9% in 2019 and 10.9% in 2018. The average winter seasonal PM 2.5 level was 194 gm3 in 2020, 180 gm3 in 2019, and 200 gm3 in 2018.According to the results, the monsoon season in Delhi was the cleanest for Delhi since 2018.Compared to 44 gm3 in 2020, 46 gm3 in 2019 and 49 gm3 in 2018, the average PM 2.5 levels were 41 gm3 for the monsoon season this year.The summer of this year saw higher PM 2.5 levels than predicted.
