It’s been predicted that Delhi will continue to have ‘very poor’ air quality at least till the 3rd of December. The reason behind this is the early onset of winter, which has in turn been caused by dropping temperatures and falling speed of the wind. The rate of descent into an unhealthy air was surprising though both in terms of time taken and quality affected. The quality of the Delhi air dropped from ‘moderate’ on 29th of December to ‘very poor’ in just a day. With 9.7 degree Celsius on Wednesday, Delhi also registered the lowest temperature so far this season. This in itself ensures that polluted air stays near ground for a longer period in the day before the Sun heats up the surroundings, allowing relatively fresher and cooler air to replace it.
The Air Quality Index of Central Pollution Control Board went up by 39 points and reached 368. The particulate matter which, in layman’s language is the total of the suspended particles in the air was above the normal level of 2.5 by 400 micrograms per cubic metre – 6x the 24-hr standard at several Delhi locations including RK Puram, Anand Vihar and Punjabi Bagh. Wind speed was recorded to be as low as 1 metre per second, according to a report in The Times of India.
Ravindra Vishan, who heads the regional meteorological centre predicted that good air quality, courtesy strong wind and high temperature in past two weeks is going to change, but not for good. Vishan believes that the winds would be easterly, northeasterly from November 30t to December 3. The winds, he said will increase the moisture in the air and will bring down the visibility in the Gangetic plains. He also predicted there will be a reduction in the dispersion of aerosols which in turn will lead to shallow to moderate fog at several places in Uttar Pradesh.