Thick fog is playing havoc with holiday travel plans across the New Delhi capital region and beyond.
More than 500 flights have been delayed as the unseasonably cold weather continues.
"Heavy fog disrupted flight operations at the airport Monday, with 530 flights delayed. Twenty have been diverted and six cancelled," an airport official said.
Airlines are advising customers to check for updates before setting off for the airport.
"Owing to dense fog in north India, our flights have been impacted across India. We will continue to review the situation and provide real-time updates on our social platforms," IndiGo said.
Virtually all Indian airlines posted updates and advisories on their social channels.
Full-service carrier Vistara said it cancelled six flights to and from Delhi on Monday.
India’s weather bureau said Delhi was set to record its second coldest December since 1901, based on average temperatures for the month so far.
The dense fog has also impacted rail travel.
"Thirty trains are running late due to low visibility," a state railways official said.
