On December 4, India celebrates Navy Day to recognize the achievements and role of the Indian Navy. December 4 is celebrated as Navy Day to commemorate the decisive naval action by the Indian Naval ships on Karachi Port, which heralded the victory of India over Pakistan in the Indo-Pak War of 1971.
On December 4, the Indian Navy carried out Operation Trident, which was a devastating attack on Pakistan Naval Headquarters of Karachi. The attack was successful as it sank a minesweeper, a destroyer and an ammunition supply ship. The Indian Navy planned the attack at night as Pakistan did not have aircrafts that could carry out bombings at night.
The Indian attack consisted of 3 Vidyut class missile boats, 2 anti-submarines and a tanker. After the operation, there were no casualties from India, though 5 Pakistani sailors and over 700 men were injured. The Indian Navy's three warships -- INS Nipat, INS Nirghat and INS Veer -- played an important role in the attack.
The Indian Naval Headquarters (NHQ) in Delhi, along with the Western Naval Command, planned to attack the Port of Karachi. A strike group under Western Naval Command was formed for this mission. This strike group was to be based around the three Vidyut-class missile boats already deployed off the coast of Okha. According to NDTV, fleet reached 70 miles south of Karachi at night and after missiles were fired Pakistani vessel -- PNS Khaibar-- sunk. A number of Indian Navy personnel were honoured with gallantry awards for the operation.