Delhi’s air quality further crumbled this Tuesday and was recorded in the ‘extremely poor’ classification for most parts of the day, which authorities describe as fundamentally an aftereffect of horrible weather conditions.

Wind speed over the city dropped to almost zero between 7 pm on Monday and 8 am on Tuesday and the evening temperature was 19.8 degrees Celsius, according to the Indian Meteorological Department.

The normal air quality file of the city on Tuesday was recorded on the fringe of ‘poor’ and ‘extremely poor’ classifications with a perusing of 300, according to information from the Central Pollution Control Board.

An estimate from the Central government’s SAFAR air quality and climate estimating framework stated that in Delhi, the improvement of solid surface-level reversal and abrupt quiet wind conditions prompted a low ventilation coefficient and collection of pollutants close to the surface. A reversal is when the temperature close to the surface is lower than the temperature at a higher elevation, which sets a limit for the upward development of air and frustrates the dissemination of contaminations caught close to the surface.  The ventilation coefficient is calculated for the whole of the blending layer and the normal breeze speed. The coefficient is an essential parameter and plays an important role in the dispersion of air pollutants over a studied area.

AQI stayed in the ‘poor’ classification since 9.30 am on Tuesday until 4 pm, when 17 out of 34 air observing stations were in the ‘poor’ range, as stated by the CPCB. Regions with significant levels of air contaminations included Wazirabad, Mundka, and Dwarka. Until Monday night, the breeze heading over the city was from the northwest, which was good for the transport of contaminations from stubble burning conditions of Punjab and Haryana.

Kuldeep Srivastava, head of the IMD’s provincial climate determining centre in Delhi, said that after 7 pm on Monday, the breezes got quiet until 8 am on Tuesday, following which the breeze course changed to the east-southeast.  He further added that in the movement stage, when wind bearing is going to change, aggregation of pollutants was regularly noted. After 8 am, the breeze speed got to 10-12 kmph. However, that is not sufficient for the scattering of the pollutants.

The SAFAR included other information stating, “Quiet evening time surface breeze condition is probably going to proceed for the following two days. AQI is probably going to be in the poor to helpless classification for the following two days.”