Even though the minimum temperature in Delhi dropped below 20°C (19.4°C) for the first time in five days due to a shift in wind direction, the city’s air quality continued to deteriorate on Wednesday morning and was expected to reach the poor category by the end of the day.
At 8 a.m., the average air quality index (AQI) was 196 (moderate), down from 180 (moderate) the previous day. The air quality was expected to remain poor for the next two days due to the shift in wind direction to northwesterly and a decrease in local wind speed.
Air quality is negatively impacted by cold northwesterly winds. A decrease in temperature inhibits the spread of pollutants and also introduces smoke from Punjabi and Haryana fields, where agricultural fires are known to occur during this time of year.
For the first time since Friday, when it was 18.6°C, the minimum temperature fell below 20°C. After thereafter, the wind shifted, and Saturday’s low temperature increased to 20.9°C. It reached 23.1°C on Sunday and 24.4°C on Monday. Tuesday’s low in Delhi was 22.7°C, which is two degrees warmer than usual.
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“Clear skies will return with a change in wind direction. An official from the India Meteorological Department stated that the minimum temperature is anticipated to be below 20°C due to the chilly northwesterly winds.
Up until Friday, the air quality was probably going to be on the lower end of the poor category, according to an Early Warning System (EWS) projection. “The next six days’ forecast indicates that the air quality will probably remain in the poor to moderate range.”
The Union Earth Sciences Ministry oversees the EWS forecasting system. EWS is used by the Commission for Air Quality Management (CAQM) to monitor pollution in advance.
The AQI was recorded at 212 on Friday, the first poor air day of the winter season for Delhi. CAQM used the Graded Response Action Plan’s stage-I measurements that same day. The steps include reducing traffic on the roads, periodically using mechanized sweeping, water sprinkling on roadways, closing construction and demolition sites larger than 500 square meters that are not registered with the government, etc.
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The AQI dropped to 216 (bad) on Saturday before rising to a moderate level. Since Sunday, Delhi’s AQI has been in the moderate range.
An AQI in the range of 0 to 50 is regarded as good, 51 to 100 as satisfactory, 101 to 200 as moderate, 201 to 300 as poor, 301 to 400 as extremely poor, and 400 and above as severe.
Delhi saw 200 fair to moderate air days this year, according to CAQM on Monday. This is only the second time since 2015. In the previous eight years, lockdowns caused by the Covid-19 pandemic occurred only once, in 2020.
