India, Nov. 13 -- Delhi's air quality deteriorated into the "severe" zone - the worst grade on the government's pollution scale- on Friday morning, with a thick, smoky haze continuing to envelop the Capital.

According to HT's real-time air quality dashboard, the Air Quality Index (AQI) stood at 403 at 7.30am, 82 points higher than the 24 hours before it. As HT reported earlier, Delhi's air quality deteriorated sharply on Thursday, with the city's PM2.5 concentration more than doubling in 24 hours to 244 micrograms per cubic metre by 6pm - four times the national standard.

The Central Pollution Control Board (CPCB) classifies an AQI of 0-50 as "good", 51-100 as "satisfactory", 101-200 as "moderate", 201-300 as "poor", 301-400 as "very po...