At least 21 people have been killed as a tourist boat sank off India’s Andaman and Nicobar Islands in the Bay of Bengal.

The boat, Aqua Marine, capsized yesterday afternoon off Port Blair, the capital of the islands.

An investigation is looking at the cause of the sinking amid reports the Aqua Marine was carrying too many people when it capsized, the BBC reported.

Most of those on board are believed to be Indians from Tamil Nadu and Mumbai.

The Indian air force and the coast guard rescued 29 people but one person was still missing, authorities say.

Those rescued have been taken to hospital in Port Blair, with “several of them seriously injured”, an official told AFP news agency.

Thousands of tourists a year visit the Andaman islands, which form the most easterly part of Indian territory.

The archipelago of hundreds of islands sits at least 600 miles from the mainland, and is closer to the coast of Burma.