More than three dozen flights were delayed and several trains were running late as a thick blanket of fog enveloped Delhi and nearby regions on Monday morning.
Morning temperatures were down several notches, and visibilty was at a bare minimum severely, spelling trouble for schoolchildren and early office-goers.
TV reports said than more than 50 trains across the north, including the North-East Express and Mahabodhi Express were running late by several hours due to a thick blanket of fog.
Meteorological officials have predicted temperatures in the city to be around 16 degrees maximum and around 5 degrees minimum.
CNN-IBN reported that dense fog affected other cities in the region as well, with Chandigarh airport remaining closed for the second day in a row.
On Sunday, Delhi recorded the season's coldest day with a maximum of 15 degrees Celsius, which is at least seven notches below normal.
There was no respite from the cold across the entire North . While 8 people died in Uttar Pradesh from the severe cold, three others died of suffocation in Delhi after they lit a coal fire to keep themselves warm.
In Jammu and Kashmir, Chillai-Kalan - the 40-day harshest period of winter - began on Sunday, increasing chances of the first snowfall of the season.
In Rajasthan, extreme cold conditions hit normal life, with Churu experiencing a near-freezing 0.5 degrees Celsius.