NEW DELHI — A dense morning fog on Tuesday delayed flights in and out of New Delhi’s airport and disrupted road and train travel in northern India for a third straight day.

According to First Post over 500 flights were delayed and more than 20 cancelled which includes 97 international flights.

More than 60 flights were affected at Indira Gandhi International Airport, the Press Trust of India news agency said. A backlog of flights caused delays even after the fog had lifted.

Visibility was somewhat better than the previous two days, when hundreds of flights were delayed or cancelled.

The thick fog made for hazardous road conditions, and forced the cancellation or late departure of many long-distance trains. Indian media reported at least five fatalities in fog-related road accidents.

“The area I come from has no streetlights,” said Dhurinder Singh, the 50-year-old driver of a three-wheeled, motorized taxi known as an auto rickshaw. “There could be a pile-up of cars ahead on the road that causes me to have an accident.”

Fog often descends on northern India in the winter months. The morning low in New Delhi on Tuesday was 8 degrees Celsius (46 Fahrenheit).