Dense fog engulfed the national capital region on New Year on Monday with the visibility dropping to zero. A large number of flights and trains were delayed.

The minimum temperature was recorded at 5.7 degrees Celsius, a notch below the season's average.

Operations at the Indira Gandhi International (IGI) Airport here were severely affected due to low visibility.

According to an airport official, flights were stopped from taking off between 6 and 10 a.m., while landing of almost all flights were delayed.

At least 15 trains were cancelled while 56 trains were running late and 20 have been rescheduled due to fog in several parts of northern India.

A shallow fog would continue throughout the region all through the day, the Met said. The visibility which was 1,500 metres at 3.30 a.m. dropped rapidly to zero at 5.30 a.m.

The maximum temperature was likely to hover around 23 degrees Celsius, an India Meteorological Department official said.

The humidity at 8.30 a.m. was 100 per cent.

Sunday's maximum temperature settled at 23.9 degrees Celsius, while the minimum was recorded at 6.4.