Operation Trident was an offensive operation launched by the Indian Navy on Pakistan's port city of Karachi during the Indo-Pakistani War of 1971. Operation Trident saw the first use of anti-ship missiles in combat in the region. The operation was conducted on the night of 4â5 December and inflicted heavy damage on Pakistani vessels and facilities. While India suffered no losses, Pakistan lost a minesweeper, a destroyer, a cargo vessel carrying ammunition, and fuel storage tanks in Karachi. Another destroyer was also badly damaged and eventually scrapped. India celebrates its Navy Day annually on 4 December to mark this operation. Trident was followed up by Operation Python three days later.