Indian Navy admitted five sailors in hospital Wednesday after they suffered suffocation on the Russian-origin Kilo Class submarine INS Sindhuratna off the coast of Mumbai.The sailors inhaled smoke on board the submarine during a sea-testing exercise, according to Indian media reports.A leakage in the battery compartment of the submarine suffocated the five sailors, Navy sources told the Press Trust of India (PIT) here.“This is the tenth accident involving an Indian Navy warship and the third submarine mishap in the last seven months,” PTI said. In August 2013, INS Sindhurakshak sank in the Mumbai naval harbour after an explosion killing all 18 personnel on board.