Favourable winds give Delhi its best air quality in 22 days

Delhi's air quality improved from "very poor" to "poor" and the 24-hour average air quality index (AQI) read 290 on Tuesday with favourable wind speed, up to 25 kmph, aiding dispersion of pollutants over the last two days. This is the second best 24-hour average AQI reading this month since November 1 (281).

Delhi has seen "very poor" or "severe" air quality on the rest of the days.

Officials at the India Meteorological Department said winds gusting up to 20 kmph on Sunday and 25 kmph on Monday led to a marked improvement in the air quality and visibility.


The reason why Delhi's air quality on Sunday (349) and Monday (311) was recorded in the "very poor" category is that the AQI reading at any given time is an average of AQIs recorded in the previous 24 hours.

Neighbouring Faridabad (279), Ghaziabad (268), Greater Noida (255), Gurgaon (276) and Noida (252) also saw a marked improvement in the air quality.

An AQI between zero and 50 is considered "good", 51 and 100 "satisfactory", 101 and 200 "moderate", 201 and 300 "poor", 301 and 400 "very poor", and 401 and 500 "severe".

The Ministry of Earth Sciences' air quality monitor SAFAR said transport-level winds are likely to slow down and change direction from northwest to south-southeast on Wednesday leading to further improvement in the air quality, albeit within the "poor" category.

Local surface wind speed will be relatively low for the next three days and reduce dispersion of pollutants. Surface winds are likely to pick up from November 27.

The air quality is likely to be within the poor category for the next three days, it said.

Stubble burning accounted for 3 per cent of Delhi's PM2.5 pollution on Tuesday. The Delhi government on Monday lifted the ban on construction and demolition activities in view of improvement in the air quality and the inconvenience caused to workers.

The government will take a call on the reopening of schools, colleges and other educational institutions and work-from-home for its employees during a review meeting on Wednesday.

"We will also discuss if CNG-operated trucks carrying non-essential items can be allowed to enter Delhi if the situation continues to improve," Environment Minister Gopal Rai said.

The city government had on Sunday night extended work-from-home for its employees and the ban on the entry of trucks carrying non-essential items till November 26 to combat air pollution and minimise its health effects.