India, Dec. 19 -- Dense fog enveloped parts of Delhi as the air quality inched closer to the 'severe' category on Friday morning. The air quality index (AQI) was 380 (very poor) at 9am, according to the Central Pollution Control Board (CPCB) data.

The India Meteorological Department (IMD) issued a red alert at 8:20am on Friday, citing dense fog conditions across the city for the next two hours, with visibility dropping to below 50m.

The minimum temperature for the day remained unchanged and was logged at 9degC.

The city's 24-hour average AQI was recorded at 373 (very poor) at 4pm on Thursday.

December has already seen three 'severe' air days between December 13-15.

While the air quality slightly improved over the last few days, owing...