(ET)
It may well have been September: clear blue skies and strong winds greeted Delhiites on Sunday morning. Except, it wasn’t. Deep into November and right after one of Delhi’s worst smog episodes, the capital experienced its cleanest air in terms of AQI since November 6, with a reading of 215 (poor) on Central Pollution Control Board’s daily bulletin at 4pm.
In contrast, the AQI reading on Friday was 458 (severe). The dramatic turnaround was because of a number of meteorological factors, which included strong winds ranging between 25 and 30 km/hr, clear skies, reduced humidity and a high boundary layer that allowed faster dispersal of pollutants. This was also the first time since October 23 when Delhi-NCR’s average PM 2.5 concentration over 24 hours was below 100 µg/m3. Met officials said the air quality might improve to “moderate” by Monday before it starts to deteriorate gradually with a reduction in wind speed.
