What it links
The Bay of Bengal to the Gulf of Mannar, between Tamil Nadu and Sri Lanka.
Adam’s Bridge
A 30-mile chain of shoals, splitting the strait from the Gulf of Mannar.
Its depth
Just 1 to 10 metres — too shallow for big ships to cross.
Its bridge
Pamban Bridge, India’s first vertical-lift sea bridge, opened 2025.
The Basics
A Strait, a Bridge, and a Bay
- What it is: a narrow strait of the Bay of Bengal, lying between Tamil Nadu and Sri Lanka.
- What it connects: it joins the Bay of Bengal in the north to the Gulf of Mannar in the southwest.
- Adam’s Bridge: also called Ram Setu, this is a chain of limestone shoals inside the strait. It runs about 30 miles between Pamban Island in India and Mannar Island in Sri Lanka.
- A real divider: Adam’s Bridge marks the line between the Palk Strait to its north and the Gulf of Mannar to its south.
- The name: the strait is named after Robert Palk, a British colonial-era governor of Madras.
Worked example: picture a shallow, 30-mile-long ridge of rock sitting just under the waves. That ridge is Adam’s Bridge. Everything north of it is the Palk Strait. Everything south of it is the Gulf of Mannar. One landmark, two named seas.
True or False: Adam’s Bridge separates the Palk Strait from the Gulf of Mannar.
Its Shallow Water
Too Shallow for Big Ships
- Shallow water: the strait is too shallow for large ships to sail straight through. Depths mostly run between 1 and 10 metres.
- The long detour: this forces big ocean-going ships to sail all the way around Sri Lanka instead, adding real distance and time to their trip.
The Pamban Bridge
A Bridge That Lifts Itself Out of the Way
- Pamban Bridge: links Rameswaram’s Pamban Island to the Tamil Nadu mainland. It’s India’s first vertical-lift sea bridge.
- How it works: a 72-metre middle span rises straight up to let ships pass underneath. The older bridge it replaced had a middle section that swung open sideways instead.
- A real milestone: the new bridge opened in April 2025, over a hundred years after the first Pamban Bridge joined the island to the mainland in 1914.
Think it through. Why build a bridge that lifts up, instead of just building it tall enough for ships to pass under from the start?
Show the explanation
A bridge tall enough for every ship, all the time, would need very long, steep approach roads on both ends. That’s costly, and hard to build on a small island. A lifting span solves this cheaply. The bridge stays low most of the time, easy to use for road and rail traffic. It only rises on the rare occasion a tall ship needs to pass.
True or False: The Pamban Bridge is India’s first vertical-lift sea bridge.
The Real Exam Trap on This Topic
- The trap: exams count on you mixing up three water bodies here. They are close together, but not the same. They are the Palk Strait, Palk Bay, and the Gulf of Mannar.
- The real test: the Palk Strait sits on the Bay of Bengal side. Adam’s Bridge separates it from the Gulf of Mannar to the south. Palk Bay is the shallower, more closed-in northern part of this same stretch of sea.
- How to prepare: pin each name to one exact spot on the map, instead of treating “the water between India and Sri Lanka” as one single patch.
- CAPF (ACs) 2026 Asked which island-and-water-body pairs are correct, out of four given, including Vaan Island and the Gulf of Mannar. Answer: only two hold up. They are Kharg with the Persian Gulf, and Vaan with the Gulf of Mannar. Tuti Island is actually in Sudan. Qeshm sits in the Persian Gulf, not the Arabian Sea. View CAPF (ACs) 2026 Paper, Q73 →
- NDA/NA-I 2017 Asked which of four listed areas are India’s major coral reef zones. The four were the Gulf of Kachchh, Gulf of Mannar, Lakshadweep, and Andaman and Nicobar. Answer: all four are genuine major reef zones. This includes the Gulf of Mannar, right next to the Palk Strait. View NDA/NA-I 2017 Paper, Q116 →
The Sethusamudram Canal Project
A Canal That’s Been Proposed Since 1860
- The idea: the proposed Sethusamudram Shipping Canal Project would dredge a deep channel through this shallow stretch, joining the Palk Strait straight to the Gulf of Mannar.
- A long history: the idea goes back to 1860, first raised by British engineer A. D. Taylor. The Indian government formally proposed it again in 1955.
- Approved, then halted: the Union Cabinet approved the project in 2005. It was put on hold in 2007, after a Supreme Court case. Petitioners argued that dredging through Adam’s Bridge would damage a site of religious importance.
- Still stalled: environmental groups have separately warned that dredging could harm the coral reefs of the nearby Gulf of Mannar Marine National Park.
- The latest: legal disputes continue. The Tamil Nadu Assembly has passed a resolution asking the Union government to revive the project.
Palk Bay’s Fishing Dispute
Another Round of Arrests (2026)
Another Round of Arrests (2026)
- The incident: on 11 April 2026, the Sri Lankan Navy detained 12 Indian fishermen off Karainagar, near Jaffna. Their trawler was seized too, over alleged illegal fishing. (Source: Deccan Herald)
- A recurring pattern: over 100 Indian fishermen had already been detained by Sri Lankan authorities in 2026 alone. It’s part of this same long-running Palk Bay dispute. (Source: Deccan Herald)
- Why it matters here: it’s the latest example of exactly the maritime-boundary friction explained earlier in this article’s Great to Know section.
Quick Q&A
Q: What separates the Palk Strait from the Gulf of Mannar?
A: Adam’s Bridge, a 30-mile chain of limestone shoals between Pamban Island, India, and Mannar Island, Sri Lanka.
Q: Why can’t big ships sail straight through the Palk Strait?
A: It’s too shallow, mostly just 1 to 10 metres deep, so large ships must sail around Sri Lanka instead.
Q: What’s special about the Pamban Bridge?
A: It’s India’s first vertical-lift sea bridge — a 72-metre span rises to let ships pass, opened in April 2025.
Q: Why is the Sethusamudram Canal Project still stalled?
A: A 2007 Supreme Court case over damage to Adam’s Bridge, plus environmental concerns for the nearby Gulf of Mannar reefs.
✅ Test Yourself
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