India’s Interisland Channels: Nine Degree, Ten Degree, and Duncan Passage

What does the Nine Degree Channel separate?

The Nine Degree Channel runs through the Lakshadweep archipelago, in the Arabian Sea. It separates Minicoy Island, at the archipelago’s southern end, from the main Lakshadweep group further north. That group includes the Amindivi Islands. The channel is roughly 200 km wide, and reaches depths of over 2,500 metres. It takes its name from lying near the 9-degree line of north latitude.

What is Lakshadweep built from?

Lakshadweep is India’s smallest Union Territory, made up of coral atolls and reef islands. Like the rest of Lakshadweep, Minicoy is a coral atoll, built up from ancient reef growth. Its large lagoon is one of the biggest in the entire archipelago. Minicoy is also known for its tall historic lighthouse and its own distinctive tuna-fishing traditions.

What sits on the other side of the channel?

The main Lakshadweep group, north of the channel, includes islands such as Kavaratti, Agatti, and Amini. Kavaratti is the administrative capital of Lakshadweep, and it sits north of the Nine Degree Channel. Picture one dotted line of islands running north to south. Below the channel sits Minicoy, alone. Above it sits the rest of Lakshadweep, clustered around Kavaratti.

What does the Ten Degree Channel separate?

The Ten Degree Channel separates the Andaman group from the Nicobar group. Specifically, it splits Little Andaman from Car Nicobar. The Andaman and Nicobar Islands together form one Union Territory, but they remain geologically and culturally quite distinct. The channel runs about 150 km wide, north to south, near the 10-degree line of latitude.

How does its origin differ from Lakshadweep’s?

Unlike Lakshadweep’s coral atolls, the Andaman and Nicobar Islands are the tips of a long submerged mountain range. That same range produces the Andaman Trench and Barren Island. Don’t confuse this channel with the Nine Degree Channel: this one splits the Andaman group from the Nicobar group, not the Lakshadweep islands. Car Nicobar sits on its southern side. It is the Nicobar group’s most populous island, its administrative centre, and home to a major airbase.

What does Duncan Passage separate?

Duncan Passage lies within the Andaman group itself, between South Andaman and Little Andaman. South Andaman holds Port Blair, the Union Territory’s capital and its largest overall settlement. The Nine and Ten Degree Channels separate entire island groups. Duncan Passage splits two islands within the same Andaman chain instead.

Who uses this passage, and who lives nearby?

Duncan Passage is named after a British naval officer. Many islands and channels here still carry British-era names alongside newer official Indian names. Local ferries and small vessels regularly use it to move between South Andaman and Little Andaman. Little Andaman is home to the Onge, one of the Andaman Islands’ indigenous tribal communities, protected under special regulations.

What role do these channels play in shipping and security?

The Nine Degree Channel is a major international shipping route. It carries traffic between the Persian Gulf, Sri Lanka, and Southeast Asia. Further east, the Six Degree Channel sits near Great Nicobar, close to the approaches of the Strait of Malacca. Nearly 80% of China’s oil imports pass through the Strait of Malacca each year, giving this nearby channel real strategic weight for India’s own planners. Both the Nine and Ten Degree Channels sit close to India’s western and eastern maritime approaches, giving them real naval significance. India’s tri-service Andaman and Nicobar Command monitors and secures these channels and the wider surrounding waters. It is India’s only tri-service theatre command, combining army, navy, and air force units under one leadership.

2025-26 update: a strategic blueprint, dated 3 September 2026, highlighted the Rs 81,000-crore Great Nicobar Island Development Project. It flagged the project’s spot near the Six Degree Channel, close to the approaches to the Strait of Malacca (source: IBG News, 3 September 2026).

• The plan includes a 3,500-metre runway, and a big container port at Galathea Bay, built to boost sea patrols and cargo movement in the area.
• The blueprint also flags the region’s seismic activity. It calls for protecting coral reefs and leatherback turtle nesting sites near Galathea Bay.