ANSWER: Indo-Pakistani War of 1971
Explanation:
- Every year 4 December is celebrated as the Navy Day in India.
- It is to commemorate the start of Operation Trident during the Indo-Pakistani War of 1971.
- In one-night attack the Indian Navy sank three vessels near the largest Pakistani port of Karachi. Operation Trident resulted in the first use of anti-ship missiles in the region.
