The ban on flights from six cities with high Covid-19 prevalence, including Delhi and Mumbai, to Calcutta has been extended till August 15 following an intimation from the Bengal government.

The ban was to lapse on July 31.

Airlines officials said thousands of passengers had booked tickets on the 30-odd flights that were scheduled for August 1 and are now cancelled. There were many more bookings for the later dates till August 15, said the airlines.

The civil aviation ministry had imposed a ban on flights from Delhi, Mumbai, Chennai, Pune, Nagpur and Ahmedabad to Calcutta from July 6 to 19 following a request from the Bengal government. The ban was later extended till July 31.

On Thursday, Bengal home secretary Alapan Bandyopadhyay wrote to civil aviation secretary P.S. Kharola: “I am further directed to inform you that the suspension of flights from the aforesaid cities (the six cities mentioned earlier) to Kolkata will continue till 15th August, 2020.”

An official of the Calcutta airport said: “We have received a communication from the ministry that the restrictions have been extended and have conveyed the decision to the airlines.”

The Telegraph reported earlier this week that the state government wanted the ban to continue because the number of Covid-19 cases was still rising across India.

Most airlines said they had opened bookings on flights from August 1 hoping that services would resume.

IndiGo had scheduled one daily flight from Mumbai and all 180 seats for August 1 were sold, said an official of the airline.

The airline had also opened bookings for three daily flights from Chennai. The three together have 520 seats and 500 were booked for August 1, he said.

The airline had planned six flights between Delhi and Calcutta, two more than the earlier count. All flights had more than 80 per cent bookings for August 1.

“We will either refund the money or offer a credit shell to passengers depending on their demands,” said an official of IndiGo.

“There were many calls from clients to book flights from these cities but we were waiting for a formal announcement on the status of the flights,” said Anil Punjabi, chairman (east), Travel Agents Federation of India.

Airport officials said 30 flights from these six cities were scheduled to operate between Calcutta and Delhi. Now, 50 domestic flights land in the city airport and an equal number take off every day.