London (PTI): Campaigners against the controversial Sethusamudram shipping channel project have asked the Governments of India and Sri Lanka to take steps to have the "Gulf of Mannar" designated as a UNESCO World Heritage Site.

At a two-day meeting here the campaigners from several countries, including India, Sri Lanka, Mauritius, the US and Canada, said the proposed shipping channel project would threaten one of the world's most pristine marine regions, the many marine species living there and the culturally and spiritually significant Adam's Bridge also known as Ram Sethu.

Leading conservationists, ecologists and religious scholars presented the case for designating the Gulf of Mannar as a World Heritage Site and explained why the shipping channel project should be abandoned.

The Gulf of Mannar, a shallow stretch of water separating India from Sri Lanka, is south Asia's largest biosphere reserve and one of the last remaining intact ecosystems on earth, Sri Lankan ecologist Ranil Sennanayake said.

Senanayake, who has dived extensively in the Gulf of Mannar, said the Gulf of Mannar was dry land 13,000 years ago. He said divers and scientists working in the area have seen ruins of cities like Mahabalipuram and Pumpoor under water on sea bed.

"The Sethusamudram project will affect the cultural archaeology under sea and will affect biodiversity of the area. It will adversely affect the supply of drinking water in both Sri Lanka and Tamil Nadu coastal areas as villagers there depend on limestone aquifer wells for drinking water."