India, Dec. 28 -- Delhi recorded "very poor" air quality early Sunday morning as parts of the national capital woke up to dense fog and cold wave-like conditions. More than 150 flights have been delayed at Delhi's IGI airport, FlightRadar24 data showed.

While Delhi's AQI was on the brink of breaching the "very poor" category, Noida recorded "severe" air quality on Sunday, with an AQI of 415.

On Saturday, air quality in the national capital slipped into the "severe" category. The AQI stood at 385, which was "very poor", at 4 pm, according to the bulletin. It worsened through the day, rising to 390 by 6 pm and reaching 391 by 10 pm.

According to data from the Sameer app, developed by the Central Pollution Control Board (CPCB), Delhi's AQ...