As you want I am telling Operation Trident and its follow-up Operation Python were naval offensive operations launched on Pakistan's port city of Karachi by the Indian Navy during the Indo-Pakistani War of 1971:

Operation Trident

Part of Indo-Pakistani War of 1971

Date 4–5 December 1971

Location Arabian Sea, 14 to 70 nautical miles south of Karachi port, Pakistan

Result Strategic Indian naval victory;

Partial naval blockade on Pakistan;

Belligerents

India Pakistan

Commanders and leaders

Admiral Sardarilal Mathradas Nanda

Commander Babru Bhan Yadav Rear Admiral Hasan Ahmed
CDRE Hanif Ali

CDRE Patrick J. Simpson


Units involved

Indian Navy Pakistani Navy

Strength

3 Vidyut class missile boats

2 anti-submarine Arnala class corvettes Unknown number of ships

Casualties and losses

None


Minesweeper PNS Muhafiz sunk

Destroyer PNS Khaibar sunk

Transport, MV Venus Challenger, sunk

Destroyer PNS Shah Jahan badly damaged, scrapped as result


Karachi harbour fuel storage tanks destroyed

100+ sailors killed

700+ injured