Moderate fog cloaked Delhi on Wednesday morning, lowering visibility to 400 metres and affecting road and rail traffic. A railway spokesperson said around 18 trains were running late by 1:30 to 5 hours.
Operations at the Delhi airport remained normal, an official said.
However, he said, three flights were returned or diverted to the Delhi airport due to bad weather in Chandigarh, Varanasi and Lucknow on Tuesday night.
The India Meteorological Department (IMD) said the Palam airport logged the lowest visibility level of 400 metres at 2:30 am, while it dropped to 500 metres at the Safdarjung airport at 5:30 am.
On Tuesday, visibility levels had plunged to 50 metres at both these places.
An IMD official attributed the improvement in visibility to south westerly winds at the middle tropospheric level and a consequent increase in temperatures in the past 24 hours.
However, amid low temperatures, high moisture and still winds, a layer of dense to very dense fog persisted over Punjab, Haryana, northwest Rajasthan, Uttar Pradesh, Bihar and parts of Uttarakhand.
At 5:30 am, visibility levels stood at zero in Bhatinda; 25m in Ganganagar, Amritsar and Bareilly, and 50m in Varanasi, Bahraich and Ambala.
In a statement issued at 1:30 pm, the IMD said dense to very dense fog in many/most pockets is very likely over Punjab, Haryana, Delhi and Uttar Pradesh during night and morning hours in the next 24h hours due to moisture and light winds at lower tropospheric levels over the Indo-Gangetic plains.
Fog is predicted to decrease in intensity and spread thereafter, it said.
According to the India Meteorological Department, very dense fog is when visibility is between 0 and 50 metres, 51 and 200 is dense, 201 and 500 moderate, and 501 and 1,000 shallow.
The Sadarjung Observatory, the primary weather station in Delhi, recorded a minimum temperature of 7.1 degrees Celsius, a notch below normal. The maximum temperature settled at 21.2 degrees Celsius, the lowest so far this season.
The minimum and maximum temperatures are likely to drop to 5 degrees Celsius and 20 degrees Celsius in the next few days.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)
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