The minimum temperature for the day was recorded as 7 degrees Celsius.
Railway Minister Piyush Goyal had on Thursday assured that safety of passengers and timely arrival and departure of trains are the top priorities.
It was also announced that a device to track railway signals would be installed in railway engines to help the trains move safely to ease the obstructions created due to the fog.
Transport services around Delhi have witnessed frequent disruptions in the past few days, causing inconvenience to commuters.
The government has said that it is monitoring the situation and trying to bring some improvement in the system performance.