The Central Pollution Control Board or CPCB informed the Supreme Court-mandated Environment Pollution (Prevention and Control Authority) that the situation is not likely to improve in the next one week.
"The particulates in the air are not getting dispersed due to the lack of wind while a large gap between the natural temperature and dew point, at which water droplets begin to condense, are keeping the pollutants trapped and making them float in the air," CPCB's air lab head Dipankar Saha said.
However, the air quality has not turned 'severe' yet as wind from the stubble-burning regions in Punjab and Haryana are not entering the national capital as of now.
Mr Saha said while last year's post-Diwali spike was more episodic in nature, this year the air quality has been consistently bad, making the overall situation worse than 2016.
The CPCB recorded an AQI (air quality index) of 351, which falls in the 'very poor' category, today. Yesterday, it was 328, while the day before it was 338.
A 'very poor' AQI comes with the warning that people may develop respiratory illness on prolonged exposure while exposure to 'severe' air affects healthy people and seriously impacts those with existing respiratory or cardiovascular diseases.