India's tryst with submarines began in Dec 1967 with the INS Kalvari of the Foxtrot Class from the USSR. By 1969, India had four of those. India used submarines during the war with Pakistan in 1971. There are now a total of 16 submarines in service in the Indian Navy including 1 nuclear-powered ballistic missile submarine and 7 Kilo-class submarine. Watch the video to know more