Island Groups

The Indian island territories constitute a vital physiographic division of India, structurally distinct from the mainland. They are broadly classified into two major categories based on their geographic location, structural composition, and tectonic origin: the Andaman and Nicobar Islands in the Bay of Bengal, and the Lakshadweep Islands in the Arabian Sea. Apart from these major archipelagos, India possesses numerous offshore and nearshore islands along both its eastern and western coasts.

The Andaman and Nicobar Archipelago

The Andaman and Nicobar Islands represent an elongated chain extending north to south. Geologically, they are the emergent peaks of a submerged mountain arc that marks the tectonic boundary between the Indian Plate and the Burma Microplate (part of the Eurasian Plate).

Geopolitical and Structural Subdivisions

• The Andaman Group: Divided into North Andaman, Middle Andaman, South Andaman, and Little Andaman. Port Blair, the capital of the Union Territory, is situated on South Andaman.
• The Nicobar Group: Separated from the Andaman group by the Ten Degree Channel (10° N latitude). It is divided into Car Nicobar, Little Nicobar, and Great Nicobar.
• Great Nicobar Island: The southernmost island of the archipelago, housing Indira Point (formerly Pygmalion Point), which represents India’s southernmost geographical point (6° 45′ N latitude).

Vital Channels, Straits, and Passages

• Duncan Passage: A strategic water body separating South Andaman from Little Andaman.
• Ten Degree Channel: A deep sea channel that physically separates Little Andaman (southernmost of the Andamans) from Car Nicobar (northernmost of the Nicobars).
• Coco Channel: Located north of Landfall Island (the northernmost point of the Andaman group), separating Indian territory from the Coco Islands of Myanmar.
• Sombrero Channel: A local channel separating the Little Nicobar and Central Nicobar groups.
• Great Channel (Six Degree Channel): Separates Great Nicobar Island from the Aceh province of Sumatra, Indonesia, acting as a crucial shipping lane entry point to the Strait of Malacca.

Volcanic Features and Geomorphic Anomalies

• Barren Island: Located east of Middle Andaman, it is home to India’s and South Asia’s only active volcano. Its historical eruptions date back to 1787, with active phases recorded in recent decades.
• Narcondam Island: Located northeast of Barren Island, it is a volcanic island classified as a dormant or extinct stratovolcano.
• Mud Volcanoes: Found at Baratang Island in the Andaman group, caused by the extrusion of wet subterranean mud driven by decaying organic matter and natural gas accumulation under high pressure.

The Lakshadweep Archipelago

The Lakshadweep Islands form the smallest Union Territory of India. They represent an archipelago of atolls, reefs, and submerged banks located roughly 200 km to 440 km off the coast of Kerala.

Structural Divisions and Channels

• Amindivi Islands: The northernmost group of the archipelago, consisting of islands such as Amini, Kadmat, Kiltan, Chetlat, and Bitra.
• Laccadive (Cannanore) Islands: The central group of islands, which includes Kavaratti (the administrative capital), Agatti, and Andrott.
• Minicoy Island: The southernmost and second-largest island of the archipelago, separated from the main Lakshadweep group by the Nine Degree Channel (9° N latitude).
• Eight Degree Channel: Separates the southern tip of Minicoy Island from the northernmost atolls of the Maldives archipelago.

Distinctive Geomorphic and Biological Features

• Atoll Morphology: Most islands feature a crescent-shaped coral reef on the eastern side and a shallow, calm lagoon on the western side, which protects the low-lying land from intense open-sea wave action.
• Pitti Island: An uninhabited coral islet functioning exclusively as a bird sanctuary, providing a crucial nesting ground for pelagic birds such as the Sooty Tern and Greater Crested Tern.
• Agatti Island: Houses the sole airport serving the entire Lakshadweep archipelago.
• Andrott (Androth) Island: Holds the distinction of being the largest island in terms of land area within the Lakshadweep group.

Offshore, Nearshore, and Estuarine Islands of Mainland India

Apart from the primary oceanic archipelagos, India possesses numerous islands along its continental shelf formed by river delta deposition, marine erosion, and tectonic subsidence.

Western Coast Islands

• Majuli Island: Located in Assam within the course of the Brahmaputra River, it is the largest mid-river deltaic island in the world and the first island to be designated as a distinct administrative district in India.
• Salsette Island: Located on the Konkan coast of Maharashtra, it is highly populated as it contains the metropolitan areas of Mumbai and Thane.
• Elephanta Island (Gharapuri): Located in the Mumbai Harbour, famous for its rock-cut cave temples.
• Alia Bet and Kadia Bet: Estuarine islands formed by the heavy depositional workload of the Narmada and Tapi rivers within the Gulf of Khambhat.
• Diu Island: A limestone coastal island situated off the southern coast of the Kathiawar peninsula of Gujarat.

Eastern Coast Islands

• Sriharikota: A barrier island located in Andhra Pradesh that separates Pulicat Lake from the Bay of Bengal, housing the Satish Dhawan Space Centre (India’s primary spaceport).
• Pamban (Rameswaram) Island: Situated between peninsular India and Sri Lanka in the Gulf of Mannar, connected to the mainland via the historic Pamban Railway Bridge. It forms part of Adam’s Bridge (Rama Setu).
• Wheeler Island (Abdul Kalam Island): Located off the coast of Odisha near Chandipur, serving as India’s primary missile testing and launch facility.
• New Moore Island (Purbasha/South Talpatti): A low-lying mudflat island in the Bay of Bengal off the coast of the Sundarbans delta, which was a subject of territorial dispute between India and Bangladesh until it was completely submerged by rising sea levels.
• Sagar Island: Located in the Hooghly River delta in West Bengal, it holds significant cultural importance as a pilgrimage site (Ganga Sagar).

Strategic, Security, and Ecological Trivia

Tribal Demographics and Legal Protection

• The Andaman and Nicobar Islands host vulnerable, isolated Indigenous tribal communities classified as Particularly Vulnerable Tribal Groups (PVTGs).
• Negrito Tribes (Andaman): Includes the Great Andamanese, Onge, Jarawa, and the Sentinelese (inhabitants of North Sentinel Island, who reject all external contact).
• Mongoloid Tribes (Nicobar): Includes the Shompen and Nicobarese.
• The tribal areas are heavily protected under the Andaman and Nicobar Islands (Protection of Aboriginal Tribes) Regulation, which prohibits unauthorized entry.

Exclusive Economic Zone (EEZ) Expansion

• Despite their small combined land area, the two archipelagos provide India with a vast Exclusive Economic Zone (EEZ), contributing nearly 30% of India’s total EEZ footprint. This geographic reach extends India’s strategic maritime presence into the critical sea lines of communication (SLOCs) of the Indian Ocean.

Tri-Services Command

• Port Blair serves as the headquarters of the Andaman and Nicobar Command (ANC), which is India’s first and only operational theater command integrating all three wings of the Indian Armed Forces (Army, Navy, and Air Force) to secure maritime borders and counter piracy.

Renamed Islands

• In recent years, several islands in the Andaman archipelago were renamed to honor historical figures of the Indian freedom struggle:
  • Ross Island was renamed to Netaji Subhash Chandra Bose Dweep.
  • Neil Island was renamed to Shaheed Dweep.
  • Havelock Island was renamed to Swaraj Dweep.