The test firing of an Agni-II missile from a launch pad off the Orissa coast disrupted flights operating from Calcutta or flying over the city.

The south flight information range of the city airport was closed for commercial aircraft from 9.45am to 10.30am on Tuesday because of the missile launch, resulting in the diversion of around 50 flights.

“Some of the overflying flights and a few taking off from Calcutta were delayed,” said an official of Netaji Subhas Chandra Bose International Airport.

The nuclear-capable Agni-II was test-fired from Wheelers Island near Dhamra, 80km from Balasore, around 10.06am. Services at Bhubaneswar airport, close to the test range, were however not affected.

“The notice to airmen in Calcutta had mentioned that the south flight information range would be closed from 9.45am to 10.30am, but overflying flights from southeast Asia that were entering the Calcutta skies through the Yangon range were being diverted from 8.30am. This was done to ensure that no aircraft entered the no-flying zone during the missile launch,” the airport official said.

Flights to Chennai, Hyderabad and Bangalore that usually take the Bhubaneswar route were diverted through the Nagpur, Jamshedpur and Jharsuguda routes.

Thanks to the diversion, domestic flights had to cover an extra 100 nautical miles and the overflying ones, around 150 nautical miles.

Air India’s Calcutta-Hyderabad flight, which was scheduled to take off at 9am, was delayed by 40 minutes. “Around five other flights from the city were also delayed,” said an airport official. The airlines, however, refused to comment.

Flights between Chennai and Port Blair were running behind schedule but those operating from Calcutta to the island were not affected as they flew out before the south flight information range was closed.

“The diversions were made to ensure there was no clash of routes of the commercial flights and the missile,” said P.K. Singhal, the regional executive director (east) of Airports Authority of India.

Defence sources said the notice to airmen (Notam) was issued by government agencies — based on the guidelines of the Aeronautical Information Services of the Convention on International Civil Aviation — to alert pilots.

The notice is generally issued for missile launch, air shows and parachute jump.