KOLKATA: India has announced closure of airspace over an area around the Andaman and Nicobar Islands in the Bay of Bengal and the Andaman Sea for three hours each on May 24 and May 25 for a planned air activity, which includes military exercises and weapons tests.A NOTAM stated no civilian aircraft will be allowed to use the airspace at any altitude.As a result of this, duration of flights from Kolkata to Bhubaneswar, Visakhapatnam, Hyderabad, Chennai and Bengaluru, as well as return flights will be 15-20 minutes longer on Saturday and Sunday between 7am and 10am. Instead of flying via Bhubaneswar, flights will be routed via Jamshedpur. Overflying aircraft between Southeast Asia and Europe will also be offered alternative routes as nine international routes will be closed in that period.As per the NOTAM, the restriction will be on the airspace over a polygonal area around the Andaman and Nicobar Islands with a maximum corridor length of 500km.