Delhi’s air quality remained in the “very poor” category for the 13th consecutive day on Monday as calm overnight winds continued to prevent the dispersion of pollutants.

A 24-hour average Air Quality Index (AQI) of 348 (very poor) was recorded at 8pm, marking a marginal deterioration from Sunday’s 4pm reading of 334 (very poor). The AQI was 352 (very poor) at 4pm on Saturday.

The India Meteorological Department (IMD) said fog was recorded in the capital in the early hours of the day, with visibility dipping to 800 metres at Safdarjung. It said smog is expected mainly for the remainder of Monday, particularly at night. Visibility below 1,000 metres is classified as fog but it is smog when the relative humidity is less than 75%.

An IMD official said wind speed marginally picked up to 10 km per hour during the day on Saturday and Sunday. It was expected to be around 4 to 6 km per hour on Monday. The wind direction was likely to remain easterly to south-easterly. “Winds are calm overnight, which is leading to fog and smog formation. During the day, it picks up slightly,” said the official.

Central Pollution Control Board data showed two stations—Jahangirpuri (411) and Bawana (401)—recorded air quality in the severe category. Delhi’s overall AQI touched “very poor” on October 30 and has stayed in this range since.

Source: Hindustan Times