A thick blanket of fog engulfed the national capital and its suburbs on the New Year Day with visibility dropping to zero, hitting domestic and international operations at the Delhi airport and delaying trains departing from and arriving to Delhi.
With mercury at 5.7 degrees Celsius, dropping a notch below the season's average on Sunday night, hundreds of passengers braved the morning chill as they remained stranded for hours at the airport and Delhi railway stations.
"Delhi woke up to worst fog of the season. Most of the northwestern plains are in its grip. Day temperature will fall significantly," Mahesh Palawat, Vice President at Skymet Weather, said, adding the minimum temperature of 5.7 degrees was "lowest minimum of the season".
All the terminals at the Indira Gandhi International (IGI) Airport were packed with passengers, who drove on fog-covered roads to catch their morning flights.
The visibility which was 1,500 metres at 3.30 a.m. dropped rapidly to zero at 5.30 a.m.
The flight operations at the airport were halted for about five hours. However, the visibility improved as the late morning sun broke through the blinding cloud cover, allowing some flights to take off around 11 a.m.
A visibility of at least 125 metres is needed for a flight to take off.
Arrivals at the airport were also baldy hit as only some aircraft were allowed to land. Flights can land in visibility below 50 metres if pilots are trained in CAT IIIB -- which is Category Three.
The Northern Railways said over 50 trains coming to Delhi were running late and 20 were rescheduled. Some 15 were cancelled.
The Met Department said the shallow fog would continue throughout the region all through the day. The maximum temperature was likely to hover around 23 degrees Celsius.
Pollution levels in the capital also shot up. The Air Quality Index (AQI) at various places in Delhi fell to the "hazardous" category.
Many took to Twitter to share pictures of their areas covered by the blinding fog as the hashtag #delhifog was among the most trending topics on the microblogging site.
"I wanted to say Hello 2018 by clicking the sunrise, but with this fog I can't even see my reflection to say hello to myself," tweeted @virenrawat48, posting a picture of all haze.
@pinkychandran tweeted that it was "interesting start to the New Year. In the plane from 6 a.m., waiting to takeoff. No complains though."