Dense fog covered Delhi-NCR on Friday morning with the visibility dropping to zero in some areas. At least 23 trains and several flights have been delayed due to the weather conditions.
According to the weather department, the visiblity was zero at the Delhi airport.
Northern India has been experiencing bone-chilling cold with below normal temperatures.
On Thursday, Delhiites woke up to another cold and foggy morning, as the minimum temperature in the national capital was recorded at 5.8 degrees Celsius, two notches below the season's average.
The maximum temperature settled at 18.1 degrees Celsius, two notches below the normal, an IMD bulletin said.
A spokesperson for the railways said fog impacted the schedule of "24 trains approaching Delhi" due to low visibility on Thursday.
According to the data by the Central Pollution Control Board (CPCB), the 24-hour average Air Quality Index (AQI) on Thursday settled at 348, which falls in the "very poor" category.
An AQI between zero and 50 is considered "good", 51 and 100 "satisfactory", 101 and 200 "moderate", 201 and 300 "poor", 301 and 400 "very poor", and 401 and 500 "severe".
(with PTI inputs)