They are all of coral origin,
Two groups of islands lie on the two oceans surrounding the main landmass of the subcontinent. These most likely complete the physical features of India. And, the island region is divided by the mainland as well as the seas. Thus forming two major island states-
The Lakshadweep, which lies closer to the Malabar Coast. And, these consist of clusters of coral islands collectively named Lakshadweep.
The Andaman & Nicobar Islands which are off the Bay of Bengal and lie on the Indian Ocean. These group of islands are larger in size than their western counterparts and have rich biodiversity. Because the Andaman & Nicobar islands are closer to the equator, the region also experiences equatorial climate.