Dense fog shrouds Delhi, delays over 200 flights; air quality slips to ‘poor’

Delhi’s minimum temperature stood at 9.4°C on Tuesday, a degree above normal, compared with 10.4°C recorded on Monday.

Dense fog enveloped the national capital for nearly nine hours on Tuesday, with visibility dropping to as low as 50 metres in parts of the city, disrupting flight operations at Delhi’s Indira Gandhi International (IGI) airport, where more than 200 flights were delayed between midnight and 9am, data showed.

A dense layer of fog engulfed New Delhi on Tuesday morning. (Sanchit Khanna/ HT Photo)

While the lowest visibility recorded at Safdarjung was 50 metres, it stood at 100 metres at Palam. “Visibility began dipping rapidly on Monday night itself and by 11.30pm, had already touched 100 metres. It remained in this range till 8.30am on Tuesday,” an India Meteorological Department (IMD) official said.

The IMD classifies fog as shallow if visibility is between 1,000 and 500 metres; moderate if between 500 and 200 metres; dense if between 199 and 50 metres; and very dense if below 50 metres.

Delhi’s minimum temperature stood at 9.4°C on Tuesday, a degree above normal, compared with 10.4°C recorded on Monday.

The city’s maximum temperature on Monday was 17.5°C, five degrees below normal for this time of the year. It is forecast to range between 19°C and 21°C on Tuesday as upper-level fog dissipates post noon.

The IMD has also forecast a western disturbance to affect northwest India from February 5-7. While rainfall is unlikely in Delhi, strong winds of 20–30 kmph are expected on February 6 and 7, officials said.

Meanwhile, Delhi’s air quality, which briefly improved to the moderate category on Monday morning, continued to deteriorate and remained at the higher end of the ‘poor’ category. The 24-hour average air quality index (AQI) stood at 256 at 8am on Tuesday, up from a reading of over 210 at 4pm on Monday. Forecasts indicate that the AQI is likely to improve to the ‘moderate’ category by February 5 as wind speeds increase.

“Delhi’s air quality is likely to be ‘poor’ on February 3 and 4. It is likely to be in the ‘moderate’ category by February 5,” the Centre’s Air Quality Early Warning System for Delhi said on Monday.