The dense fog has reduced the visibility to a great extent throwing normal life out of gear, say media reports.
With the visibility reduced to zero metre and runway to 100 metre, flights operations at the Indira Gandhi International (IGI) airport has been severely hit.
Several flights were delayed, while others were diverted to other cities.
The fog has also affected the train traffic as the Northern Grid power lines are down because of heavy fog conditions in parts of Punjab and Haryana.
The season's first heavy fog is not limited to Delhi but is also being playing havoc in the other parts of northern India. The region is also experiencing cold wave.