Delhi has recorded eight ‘severe’ air days so far this month when the AQI has been over 400; it has been on the brink of severe on another six days
Delhi’s air quality on Friday morning touched the ‘severe’ category after being in the ‘very poor’ category for six consecutive days until Thursday.
Delhi’s air quality index (AQI) at 7.05am on Friday stood at 401 (severe).
This is a deviation from the forecasts on Thursday, which had indicated that Delhi’s AQI was expected to remain ‘very poor’ on Friday, and possibly touching severe only on Saturday.
“Delhi’s air quality is likely to remain in the ‘very poor’ category on Friday. The air quality is likely to be in the ‘severe’ category on Saturday and back in ‘very poor’ again on Sunday,” the Early Warning System (EWS) for Delhi, a forecasting model used by the (CAQM) in NCR, had sCommission for Air Quality Management aid on Thursday.
An AQI of 51 to 100 is classified as ‘satisfactory’, between 101 and 200 is classified as ‘moderate’, between 201 and 300 is classified as ‘poor’, between 301 and 400 is classified as ‘very poor’ and over 400 is ‘severe’ by the Central Pollution Control Board (CPCB).
Last year, Delhi recorded three such days, nine in 2020, eight each in 2019 and 2018, seven in 2017, 11 in 2016 and seven in 2015.
The wind direction on Friday morning was southeasterly. The India Meteorological Department (IMD) has said there is likely to be a change in wind direction on Friday, with it largely remaining easterly, until a western disturbance brings light rain over Delhi on November 27.
Delhi’s minimum temperature is also expected to remain low, hovering around 10-11 degrees Celsus from Friday until the weekend, rising to 13 degrees by November 27. Delhi’s minimum on Thursday was 9.2 degrees Celsius – two degrees below normal and the lowest so far this season.
Low temperatures make the atmosphere more stable, aiding calm wind conditions and making the dispersal of pollutants difficult.