NEW DELHI, Jan. 2 (Xinhua) -- Fog continued to wreak havoc for the third day in a row in the Indian capital, severely disrupting air and rail traffic Tuesday.

At least 26 flights to and from Delhi's Indira Gandhi International Airport and over 100 trains have been affected due to dense fog that has enveloped the city since the early hours of the day, officials said.

"Some 20 domestic and international flights have been delayed and six have been cancelled to and from Delhi's Indira Gandhi International Airport owing to low runway visibility because of dense fog," a senior aviation official said.

Flight operations will resume once the fog clears up later in the day, he added.

"Similarly, some 64 trains have been delayed and 24 have been rescheduled to and from the two main railway stations -- New Delhi railway station and Old Delhi railway station. Over 20 trains have been cancelled," a senior Indian Railway official said.

On Sunday and Monday, several flights were affected in Delhi due to thick fog as the runway visibility levels also dropped below 50 metres. Even train services had been hit by fog.

Fog is common in northern India, particularly in the winter months of December and January, and is responsible for many road accidents.