The atoll has a roughly oval shape and was first described by ornithologist Allan Hume in 1876;[4] its total lagoon area is 57.46 km2 (22.19 sq mi).

[5][6] The 14 km long coral reef that encloses the lagoon has three small uninhabited islands on it.

[7] The atoll used to be a breeding ground for pelagic birds, including the sooty tern (Sterna fuliginosa) and brown noddy (Anous stolidus), which were formerly found in great numbers.

[8] North Islet has a small mosque built and maintained by local fishermen from Bitra, Chetlat, Kiltan and Agatti islands.

The beaches are strewn with marine litter composed mainly of oceanic flotsam deposited by currents, such as plastic bottles, glass bulbs, polystyrene foam and cans.