Visibility poor in Delhi as dense fog envelopes city; IMD issues ‘yellow’ alert

Delhi had recorded 13 straight dense fog hours between 8.30pm on Wednesday and 9.30am on Thursday, making it the longest dense fog spell of the season

A thick blanket of fog enveloped Delhi for the fifth consecutive day, with the India Meteorological Department (IMD) recording the lowest visibility of 50m at Palam in Delhi between 5.30am and 7.30am on Friday, with improved to 150m by 8 am.

A thick layer of blanket seen over Dwarka area in southwest Delhi on Friday. (Vipin Kumar/ HT Photo)

“Dense fog was observed over Delhi like the previous days, but it weakened fairly early today. Visibility will gradually improve in the coming hours,” an IMD official said.

Delhi had recorded 13 straight dense fog hours between 8.30pm on Wednesday and 9.30am on Thursday, making it the longest dense fog spell of the season. The IMD, which had initially issued a ‘red alert’ in the national capital for today, has downgraded this to a ‘yellow alert’, which is in place for the next two days.

The IMD classifies fog as ‘shallow’ when visibility is between 500m and 1,000m, as ‘moderate’ when it is between 200m and 500m, as ‘dense’ when it is between 50m and 200m and ‘very dense’ when it is lower than 50m.

Despite low visibility, no flight diversions or cancellations were reported at Delhi’s Indira Gandhi International airport, though around 25 flights were delayed. Airports classify a flight as ‘delayed’ when it is late by more than 15 minutes.

A Northern Railways spokesperson, meanwhile, said that at least 11 trains were running late by more than one hour on Friday morning. This included the Mumbai CSMT-Amritsar Express, which was delayed by more than five hours.

Delhi’s minimum temperature was recorded at 10.7°C on Friday morning, four degrees above normal, making for a warmer than usual night. It was 8.4°C a day earlier.

The maximum is expected to hover around 21°C today. It was 21.4°C on Thursday, the lowest so far this season at Safdarjung, the base station for Delhi weather.

Meanwhile, the city air continued to remain ‘very poor’, with the average air quality index (AQI) at 365 around 9 am. Forecasts state that Delhi’s air quality is likely to remain ‘very poor’ till December 31.

“Delhi’s air quality is likely to remain in the ‘very poor’ category from December 29 till December 31. The outlook for the subsequent six days shows the air quality is likely to remain in the ‘very poor’ category,” said the Early Warning System (EWS) for Delhi, a forecasting model under the ministry of earth sciences, adding that conditions were not favourable for dispersion of pollutants and any firecrackers burst on December 31 may worsen the air quality.