A blanket of fog enveloped the city this morning disrupting rail and air traffic even as the mercury plummeted sharply leaving Delhiitesshivering. 

The minimum was recored at 5.6 degree Celsius as compared to yesterday's minimum of 9.3 degree Celsius. 

Fog cover in the city disrupted air, rail and road traffic.

Over 35 trains were delayed in the morning due to dense fog in Delhi and parts of North India. 

According to a Northern Railway spokesperson, the trains which recorded disruptions due to fog included the Rajdhani Express trains from Patna, Howrah, Mumbai and Bhubaneshwar. 

These trains were running over two hours behind schedule while the other mail and express trains were reported to be running four to six hours behind their scheduled time. 

Flight operations at the IGI Airport were also disrupted with 30 flights delayed and three cancelled.Two other flights were diverted. 

The fog started to descend at the airport in the wee hours due to which the runway visibility dipped below 100 metre and the general visibility to less than 50 metre, an airport official said. 

As the runway visibility was less than the required minima for takeoff of 125 metre and 150 metre, flights were unable to take off, he said. Icy winds blowing across the city have added to the winter chill.