Chennai: Delhi’s air quality is predicted to deteriorate further, after turning ‘very poor’ on 30 November, with calm winds and low temperature allowing accumulation of pollutants.
According to the India Meteorological Department, “The city’s air quality index (AQI) on Monday was 307”.
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’.
Since the winds are predicted to slow down, the city’s air quality is likely to deteriorate further and remain in the poor to very poor category over the next couple of days.
It may be noted that calm winds and low temperatures trap pollutants close to the ground, while favourable wind speed helps in their dispersion.
The Central government’s Air Quality Early Warning System for Delhi said the city’s ventilation index- a product of mixing depth and average wind speed is likely to be 2,000 m2/s on 1 December.
Also, the share of stubble burning in Delhi’s pollution has reduced, as the harvesting season has ended.