The Andaman and Nicobar Islands in the Eastern Indian Ocean consist of many hundreds of high islands with extensive fringing reefs. Recent surveys of 110 locations in 45 reef areas showed that most of the reefs were in pristine condition with up to 135 coral species, and other reefs were degraded due to increased sedimentation, pollution, and destructive fishing. These islands are important for dugong and turtles. The best nesting sites for leatherback turtles in the Indian Ocean are on the Nicobar Islands. These have the most luxuriant coral growth in India with 69 species, along with giant clams and turtles.
Coral mining is present and there is some heavy fishing pressure.
All the coral reefs near the mainland are heavily exploited for coral sand and rock, and there is also extensive collecting of ornamental shells, gorgonians, seaweeds, holothuroids, lobsters, and sea horses. Coral and sand mining are major problems, particularly in the Gulf of Kutch where some reefs have been totally removed. Pollution and sedimentation are the greatest threats to these reefs, and industrial and oil pollution cause significant damage in the Gulf of Mannar and Palk Bay. Blast fishing and other destructive practices are persistent problems in many areas. The Maldives form the largest part of the Chagos-Laccadive ridge with 22 low atolls, extending 764 km north to south.