Palk Strait

The Palk Strait is a narrow waterway between Pamban Island in the Indian state of Tamil Nadu and Mannar Island in the Northern Province of Sri Lanka. It connects the Bay of Bengal to the Laccadive Sea. The strait is lined with a chain of low-lying islands and sandbanks known as Ram Setu (Adam's Bridge) on one side and the Gulf of Mannar on the other. The Palk Bay makes up the southwest part of the strait.

Spanning about 137 kilometers (85 miles) in length and ranging from 64 to 137 kilometers (40 to 85 miles) in width, the Palk Strait is named after Robert Palk, a governor of Madras during the British Raj from 1755 to 1763. Several rivers, including the Vaigai, flow into the strait.

Because of its shallow waters and many small islands and reefs, the strait can be tricky for large ships. However, small fishing boats and other tiny vessels manage to travel through it. Ideas have been suggested to dredge the sea to make it deeper for bigger ships and to build a bridge across it.

Geography

The Palk Strait lies between Pamban Island in the southeastern tip of the Indian state of Tamil Nadu and Mannar Island in the Northern Province of Sri Lanka. It links the Bay of Bengal to the Laccadive Sea. On one side, it is bordered by a chain of low-lying islands and sandbanks called Ram Setu (also known as Adam's Bridge), and on the other side by the Gulf of Mannar. According to the Hindu epic Ramayana, these sandbanks were once part of a bridge built by heroes to help save a princess.

The Palk Bay makes up the southwest part of the strait. It stretches for about 137 km and ranges from 64 to 137 km wide. Several rivers, including the Vaigai, flow into the strait. The water is shallow near the sandbanks, usually only 1–3 m deep, while the middle of the strait is about 20 m deep, with the deepest point reaching 35 m.

Geology

During a time called the Last Glacial Period, when sea levels were much lower, the area now known as the Palk Strait was dry land. As sea levels rose later, around 7,000 years ago, the strait became covered by water. The waves around the strait differ: to the north in the Bay of Bengal, there are larger waves called swells, while to the south in Palk Bay, the waves are smaller and caused mainly by wind. The waves near Ram Setu are not very high, averaging about half a meter.

Last Glacial Period Before Present Holocene swells wind waves significant wave heights

Transport and navigation

The Palk Strait has shallow waters and reefs, making it hard for big ships to pass through, but small fishing boats and other small crafts can still navigate these waters. Plans to dig deeper channels and even build a bridge across the strait have been suggested for many years. The idea to create a shipping channel was first shared with the British government of India in 1860, and many groups have looked into it since then. The most recent plan was the Sethusamudram Shipping Canal Project, started by the Government of India in 2005, but some people did not agree with it for religious reasons.

The Pamban Island is connected to the Indian mainland by the Pamban Bridge, which opened to traffic on February 24, 1914. A new railway bridge was finished near the old Pamban Bridge in 2024, after the old bridge stopped being used for trains in February 2023 because it wasn’t safe anymore. A road bridge next to it opened in 1988. In the past, trains traveled from Madras to Dhanushkodi at the southern end of Pamban Island, and a ferry went to Talaimannar on the Mannar Island. The railway to Dhanushkodi was destroyed during a big storm in 1964. The ferry service between Rameswaram and Talaimannar stopped in 1984.

The Palk Strait Bridge is an idea for a tunnel and bridge under the water to connect India and Sri Lanka. People first talked about it in 2002 and have checked on it many times since.