Solution:'Atolls' are commonly found near Lakshadweep. An atoll is a roughly circular (annular) oceanic reef system surrounding a large (and often deep) central lagoon. The lagoon has a depth 80-150 metres and may be joined with sea water through a number of channels cutting across the reef.Atolls are located at great distances from deep see platforms, where the submarine features may help in formation of atolls, such as a submerged island or a volcanic cone which may reach a level suitable for coral growth.
An atoll may have any one of the following three forms-
1. true atoll-a circular reef enclosing a lagoon with no island;
2. an atoll surrounding a lagoon with an island;
3. a coral island or an atoll island which is, in fact, an atoll reef, built by the process of erosion and deposition of waves with island crowns formed on them.
Atolls are far more common in the Pacific than any other ocean. The Fiji atoll and the Funafuti atoll in the Ellice/Island are well known examples of atolls. A large 'number of atolls also occur in the Lakshadweep Islands. In the South Pacific, most atolls occur in mid-ocean.
Examples of this reef type are common in French Polynesia, the Caroline and Marshall Islands, Micronesia, and the Cook Islands. The Indian Ocean also contains numerous atoll formations. Examples are found in the Maldives and Chagos island groups, the Seychelles, and in the Cocos Island group.