It was a cold morning in Delhi on Thursday with the minimum temperature settling two notches below normal.
Over 25 trains were running late by 2-6.5 hours due to shallow fog in various parts, a railway official said.
"The minimum temperature was recorded at 5.8 degrees Celsius, two notches below normal," a meteorological department official said.
The humidity level was recorded at 97 per cent.
The city witnessed moderate to dense fog in the morning. The maximum temperature will hover around 17 degrees Celsius, the official said.
The air quality was recorded in the "very poor" category (331) on Thursday morning.