At least nine flights were diverted to Calcutta on Friday from Dhaka and Guwahati because of fog at the two airports.

Five flights from Dhaka were diverted to the city between 3.30am and 5.15am, said an airport official.

Among those, three flights were from Kuwait City to Dhaka. One of those was a Kuwait Airways flight, two were operated by Jazeera Airways (a low-cost airline of Kuwait) and another by Biman Bangladesh, said the official.

A Biman Bangladesh flight from Dammam in Saudi Arabia, that was bound for Dhaka, was also diverted to Calcutta.

“All the flights returned to Dhaka after the weather improved there,” said the Calcutta airport official.

Four flights were also diverted to Calcutta from Guwahati.

IndiGo’s flight from Lucknow to Guwahati was diverted to Calcutta.

Air India Express flight from Bengaluru and two chartered flights — one from Bhopal and another from Bengaluru — all bound for Guwahati, were diverted to the Calcutta airport.

The flights went to Guwahati later in the day, said officials.

Fog in northern India also impacted the Varanasi-Calcutta flight, which was delayed by three hours, said airport sources.

The flight was to arrive in Calcutta at 1.10pm but landed after 4pm, said the source.