PM Modi condoled Sushil Kumar's demise, saying he contributed towards strengthening maritime security.
Former Navy Chief Admiral (retd) Sushil Kumar died at a military hospital today morning following a brief illness, his family said. He was 79. Mr Kumar was Navy Chief from 1998-2001.
He died around 3:30 AM at the Army Research and Referral hospital, the family said.
Prime Minister Narendra Modi condoled his demise, saying Mr Kumar contributed towards strengthening the country's maritime security.
"Admiral Sushil Kumar will be remembered for his great service to the nation. He contributed to the strengthening of our maritime security. Anguished by his demise. May his soul rest in peace," the Prime Minister's Office tweeted quoting PM Modi.
Known for his strategic thinking, Mr Kumar had pushed for significantly expanding Indian Navy's presence in the Indian Ocean Region. He was also part of the high-level group devising strategy during the Kargil war in 1999.
Mr Kumar was Chairman of the Chiefs of Staff Committee (CoSC) when India had planned Operation Parakram in the wake of the terror attack on Indian Parliament. The CoSC comprises the Army, Navy and Indian Air Force (IAF) chiefs.
He held several key posts in the Navy which included the Vice-Chief of Naval Staff, the Flag Officer Maharashtra Area and the Flag Officer Commanding-in-Chief of the Southern Naval Command.
Mr Kumar was a specialist in hydrography and amphibious warfare. The former Navy chief had authored a book titled "A Prime Minister to Remember- Memories of a Military Chief" which examined key decisions relating to defense and strategic affairs by Atal Bihari Vajpayee during his prime ministership.