Thick fog greeted Delhi residents on the first day of the new year this morning, with hundreds of passengers were stranded at the airport for several hours as flights were suspended after visibility on the runways dropped below 50 metres.
Train services too have been severely hit in Delhi and several other parts of north India.
The low visibility led to the cancellation of one flight and rescheduling of five domestic and seven International flights at the Indira Gandhi International (IGI) Airport.
All domestic and international flights from the Delhi airport were put on hold at about 6 am morning and they started taking off a little before 11 am. Arrivals were similarly affected, with only some aircraft being able to land.
There was a scramble for the elevators, staircases and the escalator to the departure hall as soon information trickled in that boarding has begun.
Planes were seen queued up at the tarmac for take-off, with the suspension of operations resulting in a massive backlog.
Visibility levels at the Delhi Airport had gone below 50 metres on Sunday morning too.
The Air Quality Index (AQI) at Delhi's Shadipur was recorded at 332, and Siri Fort at 388 - both in the 'hazardous' category. AQI at ITO was recorded at 182 ('unhealthy' category) and Dwarka at 257 ('very unhealthy' category).
At the airport's Terminal 1 or T1, the waiting hall and the area near the boarding gates were packed with people sitting on the floor and staircases waiting for word on their delayed flights. Passengers were seen arguing with airlines staff at counters about the lack of clear information and announcements.
Departures require a visibility of at least 125 metres, while planes can land in visibility below 50 metres if the pilots are trained in CAT IIIB technology for low-visibility landings that allows qualified aircraft to land in visibility of 25-50 metres.
On Sunday moring, over 40 flights were diverted to other airports and several were cancelled. The three-hour suspension of flight operations meant that it took hours for the backlog to clear. Over 270 flights were delayed.
Many tweeted photos of the overcrowded domestic terminal where passengers could be seen sitting on floors and staircases.
At railway stations across north India, hundreds of passengers were also left stranded after multiple trains got delayed due to the thick fog today. As many as 56 trains were delayed, 20 were rescheduled and 15 were cancelled, according to Northern Railways.