Record rainfall, frequent western disturbances and strong winds made this January the cleanest in Delhi since 2015. (Representational photo by Praveen Khanna) Record rainfall, frequent western disturbances and strong winds made this January the cleanest in Delhi since 2015, when the records on air quality were first put in the public domain.
According to Central Pollution Control Board (CPCB) data, Delhi’s average air quality index (AQI) this January was 279, much less than the 324 in 2021. On two days, the air quality was ‘satisfactory’, which is unusual for this time of the year. Only one ‘severe’ day was recorded. On most days, the AQI was in the ‘poor’ range.
The reason for Delhi having alarming air quality every winter has to do with its geographic location and weather conditions. Because it lies downwind from Punjab and Haryana during the paddy stubble burning season, the smoke is carried to Delhi in October and November. Thereafter, as the temperature dips and wind speed drops, the accumulation of pollutants happens easier and the air gets more polluted.
“This year, frequent rainfall has meant that accumulated pollutants were regularly washed away. The average wind speed was also a little higher than usual. Both these factors are crucial to clean air in Delhi,” a pollution control board official said.
The lack of fog, which also facilitates the accumulation and movement of pollution, during this time period is also among the reasons for cleaner air.
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