Flight and train operations continued to take a hit in the national capital for the fourth consecutive day after dense fog prevailed in Delhi since Wednesday evening, with the visibility dropping to as low as 50m yet again in some parts of the city.
The India Meteorological Department (IMD) said visibility has been below 200m at Palam since 8.30pm on Wednesday, and fell to 50m by 10 pm, though it improved slightly after 8am on Thursday morning.
“We saw fog forming early and becoming dense by Wednesday evening itself. As of 9.30am on Thursday, dense fog continued to prevail in parts of Delhi,” said an IMD official, stating there has been marginal improvement after 8 am.
“Visibility improved from 50m at 8 am to around 150m by 9am,” said the official, adding that fog will gradually clear over the next few hours.
The IMD had issued an ‘orange’ alert for Thursday, forecasting ‘dense’ to ‘very dense’ fog. In its forecast issued at 8.30am on Thursday morning, it predicted ‘cold day’ conditions in isolated parts of Delhi.
The weather department classifies it as a ‘cold’ day when the maximum temperature is 4.5 degrees Celsius or more below normal, with the minimum also being below 10 degrees Celsius. On Wednesday, some stations in Delhi recorded a maximum that was below 13°C, eight degrees below normal.
Mungeshpur in northwest Delhi recorded a high of 12.5°C, Jafarpur in southwest Delhi 12.8°C and north Delhi’s Narela was at 14.5°C. Safdarjung, Delhi’s base station for weather, was at 22°C and is forecast to record a maximum of 21°C today.
Delhi’s minimum temperature stood at 8.4°C on Thursday morning, two degrees above normal. It was 7.8°C a day earlier.
The IMD classifies fog as ‘shallow’ when visibility is between 500m and 1000m, as ‘moderate’ when it is between 200m and 500m, as ‘dense’ when it is between 50m and 200m and ‘very dense’ when it is 50m or lower.
Despite foggy conditions, no flight diversions or cancellations were reported at Delhi’s Indira Gandhi International airport today morning, though over 100 flights were delayed since Wednesday evening. The airport classifies a flight as ‘delayed’ when it is late by more than 15 minutes.
A Northern Railways spokesperson, meanwhile, said that at least 22 trains were delayed by more than one hour on Thursday morning. This included the Puri-New Delhi Purushottam Express, which was running late by more than six hours.
“As seen in winters during dense fog, trains are run at reduced speeds to avoid any mishaps,” the spokesperson said.
Meanwhile, Delhi’s air continued to remain ‘very poor’ on Thursday, improving marginally in the past 24 hours. The average air quality index (AQI) was 377 (very poor) at 9am. It was 380 (very poor) at 4pm on Wednesday. Forecasts show Delhi’s air quality is likely to remain ‘very poor’ till December 30.
“Delhi’s air quality is likely to remain in the ‘very poor’ category from December 28 till December 30. The outlook for the subsequent six days shows the air quality is likely to remain between ‘very poor’ and ‘severe’,” the Early Warning System (EWS) for Delhi, a forecasting model under the ministry of earth sciences, stated.