Flight and train services were disrupted in India's capital New Delhi for the second day running on Monday as dense fog and cold enveloped large swathes of the northern part of the country.

More than 100 flights were delayed in Delhi on Sunday but intermittent flight operations had resumed on Monday morning, said an airport official who declined to be named.

According to aviation website Flightradar24, at least 313 flights leaving Delhi were delayed and 82 flights were cancelled on Monday.

At least 18 trains to Delhi from different parts of the country were running late because of dense fog, news agency ANI, in which Reuters has a minority stake, said on X, citing a railway document.

The city's Indira Gandhi International Airport was not operational from 4 a.m. to 10 a.m. on Sunday (2230 GMT Saturday to 0530 GMT on Sunday) because of dense fog, the official said, leading to massive delays at airports across the country.

Social media and news channels showed angry passengers arguing with airport staff at New Delhi and other airports and one video showed a man punching a pilot announcing a delayed flight on the aircraft.

India's federal aviation minister said the use of an additional runway was being expedited, equipped with the CAT III navigation system, which enables aircraft to land even when visibility is low.

"Incidences of unruly behaviour amidst this are unacceptable, and will be dealt with strongly in line with the existing legal provisions," Jyotidaditya Scindia said in a post on X.

The country's weather office has predicted dense fog and a cold wave in New Delhi for Monday and "very dense fog" on Tuesday, with a minimum temperature of 4 degrees Celsius (39.2 Fahrenheit).

"Stuck in a plane at Delhi Airport since the past two hours (literally on the runway), X user Harteerath Singh Ahluwalia wrote on the social media platform on Monday.