The Tamil Nadu State Department of Archaeology has begun the third phase of underwater archaeological exploration off Poompuhar (Kaveripoompattinam) in Mayiladuthurai district, an ancient Chola-period port city. The work seeks to trace submerged structures and evidence of early maritime activity, and is important for understanding ancient Tamil Nadu's trade links with Sri Lanka, Southeast Asia and the West. It follows an underwater survey carried out in September 2025.