IIT Delhi recorded the highest AQI at 488, followed by Chandni Chowk at 480, North Campus of Delhi University at 479. Delhi’s air quality deteriorated into the ‘severe’ category on Friday, with the national capital recording a city-level Air Quality Index (AQI) of 403, according to data from the Central Pollution Control Board (CPCB). PM2.5 remained the dominant pollutant at most monitoring stations. Of the 59 monitoring stations, 58 reported valid data.