According to CPCB data, 22 areas in Delhi recorded severe pollution.
Delhi's air quality turned severe again on Thursday due to unfavourable weather conditions. Low wind speed stopped the dispersion of pollutants, authorities said.
Central Pollution Control Board data showed the overall air quality index (AQI) at 403. The Centre-run System of Air Quality and Weather Forecasting (SAFAR) showed an AQI of 372, which falls in the 'very poor' category.
According to CPCB data, 22 areas recorded severe pollution, while 13 areas witnessed 'very poor' air quality.
In NCR, Ghaziabad and Faridabad recorded severe air quality while Gurgaon and Noida recorded 'very poor' air quality.
The overall PM 2.5 level – fine particulate matter in the air with a diameter of less than 2.5 micrometer – was recorded at 322 and the P M10 level at 485 in Delhi, CPCB said.
The national capital recorded its second highest pollution level of the year on Sunday, with an AQI of 450. The air quality remained 'severe' on Monday and Tuesday. There was slight drop in pollution level and the air quality moved to the 'very poor' category on Wednesday.
On Thursday, the air quality again worsened and turned severe.
According to the Indian Institute of Tropical Meteorology, the air quality is likely to improve marginally on Friday. It will continue to remain in very poor category in next three days.