NEW DELHI: Delhi saw worse air pollution this October than in the same month in 2019, despite Diwali falling in October last year, CPCB data shows. Delhi averaged an AQI of 265 (poor) in October this year as compared to 234 last October.
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This despite air quality having fallen to “severe” on the final couple of days of October last year, following Diwali celebrations on the 27th. This October, the AQI did not touch severe levels but pollution was high due to meteorological factors and a sharp increase in farm fires in Punjab.
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October 2020 has, however, fared marginally better than October 2018, which had an average AQI of 269, data shows.
Kuldeep Srivastava, scientist at India Meteorological Department (IMD) and head, Regional Weather Forecasting Centre, said, “Though the monsoon withdrawal happened on September 30 this year, Delhi did not receive rainfall since September 8. In 2019, the capital received moderate showers of 47.3 mm on October 4 and trace rainfall on October 1, while there was extended monsoon till October 10 last year.”
“Moderate to high rainfall helps in settling down pollutants while light rain could make air quality worse,” Srivastava said. He added that calm winds prevailed during most of the nights in October this year impacting dispersion of pollutants while wind speed was nil in the third week of the month in 2019. While October 2017 had the highest average AQI amongst the four years, Delhi only had half the number of stations then (17) than it does now (36), while Diwali had also come much earlier that year (October 19).
Anumita Roy Chowdhury, executive director research and advocacy, Centre for Science and Environment (CSE), said, “Stubble burning started earlier this year and its contribution to Delhi’s PM2.5 was substantially high on a few days. Last year, the air quality deteriorated during Diwali time but AQI was affected this October due to stubble burning and winter conditions.”
Historical data shows November remains the most crucial month in terms of air pollution however, with the peak daily fire count generally recorded in the first week of November. This year, Diwali is also on November 14, making November an important month for air quality control.