INS Ganga sailed into Mumbai flying the flag of Rear Admiral RB Pandit, Flag Officer Commanding Western Fleet Straight from a 45 day long active patrol in the Northern Arabian sea, guarding the nation's maritime borders till her last operational day. Indain Navy frigate INS Gange placed in non-operational category on May 28, 2017 , followed by decommissioning, after how many year's of service ?