Maarg Manthan · Topic 14.7

Andaman and Nicobar Islands

Geography › India: Plains, Plateau, Coasts and Islands · Topic 14.7

The Andaman and Nicobar Islands are an archipelago of several hundred islands in the Bay of Bengal, between about 6 degrees 45 minutes and 13 degrees 45 minutes north, stretching about 590 km. They are the tops of a submerged mountain range, an extension of the Arakan Yoma, formed at the subduction zone of the Indian and Burma plates, and are separated by the Ten Degree Channel into the Andaman group in the north and the Nicobar group in the south.

6 min read · UPSC Prelims · Geography · India: Plains, Plateau, Coasts and Islands

At a Glance

Extent About 6 degrees 45 minutes to 13 degrees 45 minutes north; about 590 km
Divider Ten Degree Channel
Highest peak Saddle Peak, 737 m, North Andaman
Volcanoes Barren Island active; Narcondam dormant
Southernmost point Indira Point, Great Nicobar
Exam link UPSC Prelims, Geography: India: Plains, Plateau, Coasts and Islands

Where Does It Fit?

This is the seventh topic of the macro on India’s plains, plateau, coasts and islands. The previous topic described the broad eastern coast, and this one moves out to the island arc in the Bay of Bengal. The last topic of the macro covers the Lakshadweep islands and New Moore Island. Previous topic: Eastern Coastal Plains of India. Next topic: Lakshadweep Islands and New Moore Island.

How Did the Andaman and Nicobar Islands Form?

In short: these islands are the peaks of a drowned mountain chain created where the Indian plate dives under the Burma plate.

The Andaman and Nicobar Islands are a continuation of the Arakan Yoma range of Myanmar, which is itself an extension of the Purvanchal hills of the Himalayan system, as in Himalayan Ranges – Shiwaliks, Lesser, Greater and Trans-Himalaya. They lie on the subduction zone where the Indian plate moves under the Burma microplate of the Eurasian plate, and form an island arc, as in Ocean-Ocean Convergence and Island Arcs. The islands are made mostly of Tertiary sandstone, limestone and shale resting on volcanic rocks, similar to parts of the Himalayas. This makes the archipelago tectonically active, with frequent earthquakes and, as in December 2004, a destructive tsunami, as in Tsunami – Mechanism and Properties. The Java Trench lies to the south and the Andaman Sea behind the arc.

What Are the Groups of Islands and Their Features?

Feature	Details
Number	Counts vary by source and by what is included. The archipelago has more than 500 islands, islets and rocks, of which only about 37 are inhabited; older textbooks give 265 for the larger ones, with 203 in the Andaman group and 62 in the Nicobar group
Andaman group	North, Middle and South Andaman form the Great Andaman group, with Little Andaman to the south, separated by the Duncan Passage; Saddle Peak (737 m) in North Andaman is the highest point
Nicobar group	Car Nicobar is the northernmost and Great Nicobar the largest and southernmost; Indira Point on Great Nicobar is the southernmost point of India, only about 150 km from Sumatra; Nancowry is a central group
Ten Degree Channel	Separates the Andaman from the Nicobar group; about 150 km wide
Volcanoes	Barren Island, the only confirmed active volcano in India, which has erupted in recent years; Narcondam, a dormant volcano; mud volcanoes in Baratang
Capital	Port Blair in South Andaman, renamed Sri Vijaya Puram in 2024
Vegetation and coast	Hills with dense tropical evergreen and moist deciduous forest, mangroves and coral reefs, as in Coral Reef Types and Their Development

The islands are home to indigenous peoples, including the Great Andamanese, Jarawa, Onge and Sentinelese in the Andamans and the Nicobarese and Shompen in the Nicobars. Several of them are Particularly Vulnerable Tribal Groups, and the Sentinelese on North Sentinel Island live in isolation, protected by law, with entry to the island prohibited.

Why Are the Islands Strategically and Ecologically Important?

Strategic position: the islands overlook the entrance to the Strait of Malacca and the sea lanes between the Indian and Pacific oceans, as in Bays, Gulfs, Straits and Isthmuses. India set up its first tri-service Andaman and Nicobar Command here in 2001.
Maritime zone: they provide a large share, roughly a third, of India’s exclusive economic zone, as in UNCLOS, Territorial Waters and Exclusive Economic Zone.
Biodiversity: a hotspot with many endemic species; large areas are protected as national parks and biosphere reserves, including the Great Nicobar Biosphere Reserve, with the leatherback turtle, saltwater crocodile and Nicobar megapode.
Development and conflict: the Great Nicobar Island project, approved in 2022 at a cost of tens of thousands of crores of rupees, includes a transhipment port at Galathea Bay, an airport, a township and a power plant. It is meant to give India a hub near the main east-west shipping route, but it has been criticised for the diversion of forest land, the risk to the Shompen and Nicobarese and to turtle nesting, and for the earthquake risk, and has been examined by the National Green Tribunal.
Hazards: earthquakes, tsunami and sea-level rise; after the 2004 earthquake and tsunami, land in the Nicobar group sank by about a metre or more as the coast subsided.

As an analytical point, the islands are where security, development and conservation meet most directly, so the planning for them needs both strategic reasons and ecological and tribal safeguards, as the same remoteness that makes them valuable also makes them fragile.

Why Is This Topic Important?

Map-based Channels and peaks asked
Strategy Malacca approach
Issue Great Nicobar project

What Came Next?

The last topic of the macro describes the Lakshadweep Islands and New Moore Island. Next topic: Lakshadweep Islands and New Moore Island.

Key People and Terms

Island arc Chain of volcanic islands at a subduction zone
Ten Degree Channel Gap between Andaman and Nicobar groups
Duncan Passage Gap between South and Little Andaman
Barren Island Active volcano of India
Narcondam Dormant volcano
PVTG Particularly Vulnerable Tribal Group

Exam Corner

Points to Remember

Ten Degree Channel separates Andaman from Nicobar.
Saddle Peak is the highest point.
Barren Island is the only active volcano.
Indira Point is in Great Nicobar.
Port Blair is now Sri Vijaya Puram.

Do Not Confuse With

Barren Island and Narcondam Active versus dormant volcano
Duncan Passage and Ten Degree Channel South-Little Andaman versus Andaman-Nicobar
Car Nicobar and Great Nicobar Northernmost versus largest and southernmost

Memory Hook

Arakan’s arc in the bay: Saddle Peak up north, Ten Degree Channel in the middle, Indira Point at the tip.

Mains Angle

Questions ask about strategy and ecology. These points add depth.

Origin Subduction arc
Strategy Malacca approach
Balance Development versus tribes and forests

A Question You May Face

An original practice question, not a past paper question.

“Discuss the strategic importance of the Andaman and Nicobar Islands and the concerns about development projects there.”

How to Answer

Origin Island arc.
Geography Groups and channels.
Importance Strategy and EEZ.
Concerns Tribes, forest, hazards.

GS Relevance

Prelims: groups, channels, highest peak, volcanoes, tribes, southernmost point. GS Paper 1: physical geography; GS Paper 3: strategic importance and ecology.

Frequently Asked Questions

How were the Andaman and Nicobar Islands formed?

The Andaman and Nicobar Islands are the tops of a submerged mountain range that continues the Arakan Yoma of Myanmar. They form an island arc at the subduction zone where the Indian plate dives under the Burma plate, and are made of Tertiary sedimentary rocks over volcanic rocks.

What separates the Andaman and Nicobar groups?

The Ten Degree Channel, about 150 kilometres wide at 10 degrees north, separates the Andaman Islands from the Nicobar Islands. The Duncan Passage separates South Andaman from Little Andaman, and the Great Nicobar is the southernmost island, with Indira Point as the southernmost point of India.

Which is the active volcano of India?

Barren Island in the Andaman Sea, east of Port Blair, is the only confirmed active volcano in India, and has erupted several times in recent years. Narcondam Island to the north is a dormant volcano, and there are mud volcanoes at Baratang.

Why are the Andaman and Nicobar Islands strategically important?

The islands lie at the western entrance to the Strait of Malacca on the main shipping route between the Indian and Pacific oceans. They give India a large part of its exclusive economic zone and house the tri-service Andaman and Nicobar Command, established in 2001.

Which tribes live in the Andaman and Nicobar Islands?

The Andamans are home to the Great Andamanese, Jarawa, Onge and Sentinelese, and the Nicobars to the Nicobarese and Shompen. Several are Particularly Vulnerable Tribal Groups, and the Sentinelese of North Sentinel Island live in isolation, with entry protected by law.

PYQ Practice — Statement Analysis

1 The Andaman and Nicobar Islands are an extension of the Arakan Yoma.

True

They form a submerged island arc.

2 Barren Island is a dormant volcano.

False

It is active; Narcondam is dormant.

3 The Ten Degree Channel separates Little Andaman from South Andaman.