Please be aware of difference between Indian Ocean and Indian territorial waters. The Indian Ocean covers about 70.56 million square kilometers—that’s roughly 20% of Earth’s total ocean surface.
India’s territorial waters (the 12-nautical-mile zone from the baseline, where India has full sovereignty) add up to around 314,000 square kilometers. That includes the mainland coast plus the Andaman & Nicobar Islands and Lakshadweep.
[quick note: the Exclusive Economic Zone—where India controls resources—jumps to about 2.02 million square km, but that’s not “territorial waters” in the strict sense.]