Dense fog in the Indian capital of Delhi has led to travel chaos with air and rail travel both disrupted.

More than 30 flights were either cancelled or diverted yesterday, with at least one international service re-directed to land in Mumbai.

This followed more than 100 flights being affected on Tuesday as visibility fell to near-zero levels, the BBC reported.

Fog started to descend on Delhi airport before midnight on Tuesday and thickened early on Wednesday morning, according to the Press Trust of India (PTI).

Visibility dropped to less than 25 metres at the airport’s third runway, forcing authorities to suspend operations.

An Air India service from Hong Kong was diverted to Mumbai while other flights were cancelled yesterday. Dozens of trains were also delayed by the poor weather.

The Meteorological Office says that cold and foggy conditions will continue for the next few days.

Dense fog has also enveloped many parts of the northern states of Rajasthan, Punjab and Haryana, reports said.