A shallow layer of fog engulfed parts of Delhi on Friday morning, reducing visibility to 500 metres, as the city recorded the coldest morning of the season with mercury dipping to 5.3 degrees Celsius.
The Safdarjung Observatory, the primary weather station in the national capital, recorded the minimum temperature at 5.3 degrees Celsius, three notches below the season's normal, according to the India Meteorological Department (IMD).
This is the lowest temperature recorded so far in the season.
The Palam airport logged the lowest visibility level of 200 metres at 5:30 am. Visibility dropped to 500 metres at the Safdarjung airport at 5:30 am, the IMD said.
According to the IMD, very dense fog is when visibility is between zero and 50 metres, between 51 and 200 metres is dense fog, between 201 and 500 metres is moderate fog, and between 501 and 1,000 is shallow fog.
The maximum temperature is likely to settle around 20 degrees Celsius during the day, the IMD said.
On Thursday, road and rail services were affected as a layer of dense fog enveloped the Indo-Gangetic plains including Delhi. The Met office said the Palam and Safdarjung airport logged visibility levels of 200 metres at 5:30 am.
A railway spokesperson said 20 trains were running late by 1:30 to 4:30 hours on Thursday.
Amid low temperatures, high moisture and still winds, a layer of dense to very dense fog persisted over Punjab, Haryana, northwest Rajasthan, west and east Uttar Pradesh and Bihar.
"Satellite imagery shows continuation of dense fog layer from Punjab and northwest Rajasthan to Bihar," an IMD official said.
At 5:30 am, visibility levels stood at zero in Bhatinda; 25m in Ganganagar, Chandigarh, Gorakhpur and Bareilly, and 50m in Amritsar, Churu Bahraich and Ambala.