Dense fog hit road, rail and air traffic in New Delhi on Monday.

Vehicles moved at snail's pace till afternoon and offices started late.

It was a difficult day for students as most of the schools reopened on Monday after the winter vacation.

But the worst scene was at the airport and railway stations.

Several incoming domestic and international flights were diverted to other cities.

Flights leaving Delhi were delayed by several hours.

The Runway Visibility Range was reduced to just 75 meters in the wee hours.

Only two Indian Airlines flights -- leaving for Mumbai and Chennai -- could take off in the morning using the special illumination facility when the visibility rose to 200 metres.

International flights coming from Toronto, Kuala Lumpur, Paris, Milan, Amsterdam, Hong Kong, Frankfurt and Moscow [Images] were diverted to Ahmedabad, Mumbai, Muscat and Dubai. A Lufthansa flight coming from Lahore [Images] went back to the Pakistani city.

Domestic flights reaching Delhi from Goa [Images], Kolkata, Bangalore, Ahmedabad, Mumbai, Indore, Baroda, Pune and Thiruvananthapuram were diverted to Jaipur, Lucknow, Mumbai, Ahmedabad, Indore and Baroda.

Eighteen flights coming from Mumbai, Pune, Hyderabad, Ahmedabad, Kolkata, Bangalore, Bhopal and Chennai were cancelled.

Contact numbers at Delhi airport: 25675126, 25652011, 25652021 and 25696021.

The scene at the three major railway stations -- New Delhi, Old Delhi and Nizamuddin -- was equally chaotic.

Passengers reached the stations only to find that all trains were running late by two to six hours. Many trains were even cancelled. Relatives of passengers ran from one counter to another to get information.

In all, 62 trains were affected.

Kalindi, Lal Qila, Unchahar and Saryu Yamuna express trains were cancelled.

Nine trains, including the Ranchi Rajdhani express, arriving in Delhi were delayed by up to seven hours. The Sadbhavna Express coming from Sultanpur was delayed by 14 hours.

Fourteen trains, including the Rajdhani Express to Bhubaneshwar, were delayed by two to six hours. The Kaifiyat and Sadbhawna trains to Azamgarh and Jabalpur, respectively -- scheduled for Monday afternoon -- will leave on Tuesday at 0330 IST and 0400 IST.