The sedimentary basins of India, onland and offshore up to the 200m isobath, have an area extent of about 1.79 million sq. km. So far, 26 basins have been recognized and they have been divided into four categories based on their prospective degree as presently known. In the deep waters beyond the 200m isobath, the sedimentary area has been estimated to be about 1.35 million sq. km. Thus, the total area works out to 3.14 million sq. km.