India, March 25 -- China has significantly expanded its ocean mapping and monitoring operations across the Pacific, Indian and Arctic oceans, building a vast database of underwater terrain and environmental conditions.

Naval experts say this effort could play a critical role in future submarine warfare, particularly in a potential conflict with the US and its allies.

One of the key vessels involved is the Dong Fang Hong 3, operated by the Ocean University of China.

Ship-tracking data shows the vessel conducted repeated missions between 2024 and 2025 near Taiwan, Guam, and across strategic waters in the Indian Ocean.

It also surveyed routes near Sri Lanka and Indonesia, including approaches to the critical Malacca Strait.

While Chines...