The Gulf of Mannar is a large shallow bay forming part of the Laccadive Sea in the Indian ocean.
Project boosters emphasize the benefits of a direct shipping route that connects India's east and west coasts without the long trip around Sri Lanka; environmentalists have warned against the grave damage such a project could cause to the sea life and fisheries of the Palk Strait and the Gulf.
The Palk Strait is a strait between the Tamil Nadu state of India and the Mannar district of the Northern Province of the island Nation of Sri Lanka.
It connects the Bay of Bengal in the northeast with the Palk Bay in the southwest.
The strait is 33 to 51 miles (53 to 82 km) wide... Adam's Bridge separating Palk Strait from the Gulf of Mannar.