The channel separating the Andaman Island from the Nicobar Islands is known as

1. Introduction to India's Archipelagos (basic)

Welcome to the beginning of our journey through Indian Geography! To understand India's physical form, we must look beyond the mainland to its two magnificent oceanic arms: the Bay of Bengal and the Arabian Sea. India possesses a total of 615 islands, a vast maritime spread where 572 islands lie in the Bay of Bengal and the remaining 43 are nestled in the Arabian Sea Geography of India, Physiography, p.66. These aren't just patches of land; they represent two completely different geological stories.

The Andaman and Nicobar Islands in the Bay of Bengal are essentially the visible tips of submarine mountains. Geologists believe these islands are a physical extension of the Arakan Yoma mountain range of Myanmar that has been partially submerged INDIA PHYSICAL ENVIRONMENT, Structure and Physiography, p.15. This group is broadly split into two: the Andaman group in the north and the Nicobar group in the south. The vital boundary that keeps them apart is the Ten Degree Channel, named so because it lies directly on the 10°N latitude.

In contrast, the Lakshadweep Islands in the Arabian Sea have a biological origin. These are coral islands (atolls), built over thousands of years by tiny marine organisms. Unlike the rugged, mountainous terrain of the Andamans, Lakshadweep is characterized by flat landscapes, lagoons, and a complete absence of hills or streams Geography of India, Physiography, p.68. A key navigation marker here is the Eight Degree Channel, which separates the Indian territory of Lakshadweep from the neighboring nation of Maldives.

Feature	Andaman & Nicobar Islands	Lakshadweep Islands
Location	Bay of Bengal	Arabian Sea
Geological Origin	Tectonic/Volcanic (Submerged Mountains)	Coral (Atolls)
Major Channel	Ten Degree Channel (Separates A & N)	Eight Degree Channel (Separates from Maldives)

Sources: Geography of India, Physiography, p.66; INDIA PHYSICAL ENVIRONMENT, Structure and Physiography, p.15; Geography of India, Physiography, p.68

2. Geological Origin and Relief Features (intermediate)

To understand the origin of the Andaman and Nicobar Islands, we must look beneath the ocean. These islands are actually the elevated portions of a submerged mountain range, often considered a southward extension of the Arakan Yoma range in Myanmar. Geologically, they were formed during the Tertiary period as part of the same tectonic processes that created the Himalayas. While the Andaman group is primarily mountainous, the Nicobar group features significant coral origins Geography of India, Majid Husain (9th ed.), Physiography, p.68. The entire archipelago is a geological marvel, acting as a bridge between the Indian, Malaysian, and Myanmarese floral strains Geography of India, Majid Husain (9th ed.), Regional Development and Planning, p.90.

The archipelago is broadly divided into two clusters: the Andaman group in the north and the Nicobar group in the south. These two are separated by the Ten Degree Channel, a water body approximately 150 km wide that sits exactly on the 10°N latitude INDIA PHYSICAL ENVIRONMENT, NCERT Class XI, Structure and Physiography, p.15. In terms of relief, the islands are characterized by rugged mountains and narrow valleys. The highest point in the entire chain is Saddle Peak (738 m), located in North Andaman, followed by Mount Thuiller (642 m) in Great Nicobar INDIA PHYSICAL ENVIRONMENT, NCERT Class XI, Structure and Physiography, p.15.

Unlike the Indian mainland, this region is tectonically active. It hosts India’s only active volcano on Barren Island, which recently showed activity in 2017, and an extinct volcanic island called Narcondam Physical Geography by PMF IAS, Volcanism, p.156. Because of their location near the equator, these islands experience convectional rainfall and are covered in dense tropical rainforests, providing a unique equatorial climate within Indian territory INDIA PHYSICAL ENVIRONMENT, NCERT Class XI, Structure and Physiography, p.15.

Feature	Andaman Group	Nicobar Group
Number of Islands	Higher density (majority of the 556 islands)	Fewer islands (roughly 22 main islands)
Highest Peak	Saddle Peak (738 m)	Mount Thuiller (642 m)
Geological Note	Primarily submerged mountain peaks	Strong coral origin presence

Sources: Geography of India, Majid Husain (9th ed.), Physiography, p.66, 68; Geography of India, Majid Husain (9th ed.), Regional Development and Planning, p.90; INDIA PHYSICAL ENVIRONMENT, NCERT Class XI, Structure and Physiography, p.15; Physical Geography by PMF IAS, Volcanism, p.156

3. Strategic Importance and the Indo-Pacific (intermediate)

The Andaman and Nicobar Islands are far more than just a beautiful tourist destination; they are India's primary maritime bastion in the Bay of Bengal. Geologically, these 572 islands are essentially the peaks of a submerged mountain range — an extension of the Arakan Yoma range in Myanmar — making them largely tectonic and volcanic in origin Majid Husain, Geography of India, Physiography, p.66. This stands in sharp contrast to the islands in the Arabian Sea, like Lakshadweep, which are primarily coral formations.

The archipelago is broadly divided into two major clusters: the Andaman group in the north and the Nicobar group in the south. The critical geographical feature that separates these two is the Ten Degree Channel. This channel is approximately 150 km wide and is named so because it lies directly on the 10° N latitude line Majid Husain, Geography of India, Regional Development and Planning, p.90. Understanding this division is vital for UPSC because this channel serves as a major maritime highway for international shipping moving toward the Strait of Malacca, the gateway to the Indo-Pacific.

Feature	Andaman Islands	Nicobar Islands
Count	Larger group (approx. 556 islands total in UT, majority in Andaman)	Smaller group (approx. 22 main islands)
Inhabited	26 islands inhabited	10-11 islands inhabited
Key Tribes	Jarawas, Sentinelese, Onges	Shompens, Nicobarese

Beyond their physical structure, these islands are ecological powerhouses. They are covered in dense tropical rainforests featuring a unique mix of Indian, Malaysian, and Myanmarese flora Majid Husain, Geography of India, Regional Development and Planning, p.90. Strategically, their location allows India to monitor the busy sea lanes of the Indo-Pacific, making them the "unsinkable aircraft carrier" of the Indian Ocean NCERT Class VII, Exploring Society, Geographical Diversity of India, p.21.

Sources: Geography of India (Majid Husain), Physiography, p.66-68; Geography of India (Majid Husain), Regional Development and Planning, p.90; Exploring Society: India and Beyond (NCERT Class VII), Geographical Diversity of India, p.21

4. Indigenous Tribes and PVTGs of the Islands (intermediate)

The Andaman and Nicobar Islands are home to some of the world's most ancient and isolated indigenous communities. These tribes are broadly classified into two distinct ethnic groups based on their racial origins and geographical location. The Negrito group inhabits the Andaman Islands, while the Mongoloid group resides in the Nicobar Islands. This distinction is vital for understanding the human geography of the archipelago, as the two groups have entirely different physical characteristics, languages, and ancestral roots Majid Husain, Geography of India, Cultural Setting, p.10.

In the Andaman group, we find the Great Andamanese, Onge, Jarawa, and the Sentinelese. The Sentinelese are noted as the most isolated of all groups, fiercely maintaining their independence from modern civilization Majid Husain, Geography of India, Regional Development and Planning, p.90. These Negrito tribes are characterized by short stature (typically around 150 cm), frizzy hair, and dark skin, believed to have migrated from the Malaysian Peninsula thousands of years ago. Interestingly, while many tribal populations are dwindling, the Jarawa population saw a significant increase of approximately 62% between 2001 and 2016 Majid Husain, Geography of India, Cultural Setting, p.26.

Moving south across the Ten Degree Channel to the Nicobar Islands, the tribal landscape changes. Here, the Nicobarese and the Shompen represent the Mongoloid lineage. Unlike their Negrito counterparts, these groups share physical traits with Southeast Asian populations. Most of these tribes are classified as Particularly Vulnerable Tribal Groups (PVTGs) due to their small, stagnant, or declining populations, low literacy levels, and use of pre-agricultural technology.

Region	Racial Group	Major Tribes
Andaman Islands	Negrito	Great Andamanese, Jarawa, Onge, Sentinelese
Nicobar Islands	Mongoloid	Nicobarese, Shompen

Sources: Geography of India, Cultural Setting, p.10; Geography of India, Regional Development and Planning, p.90; Geography of India, Cultural Setting, p.26

5. Ecology and Environmental Protection (basic)

When we look at the physical geography of India, the ecological wealth of our islands and coastlines is just as significant as the mountains or plains. The Andaman and Nicobar Islands, an archipelago separated by the Ten Degree Channel (a 150 km wide stretch of water), are not just strategic outposts but are home to some of the world's most vibrant coral reef ecosystems and mangrove forests. These ecosystems act as natural buffers against coastal erosion and support a massive variety of marine life.

Coral reefs in India are classified into four types based on their formation and location. While the Andaman Islands are primarily characterized by fringing reefs (which are contiguous with the shore), the Nicobar Islands and Lakshadweep are known for barrier reefs and atolls Environment, Shankar IAS Academy, Aquatic Ecosystem, p.51. These reefs are highly sensitive; they face threats from bleaching, marine pollution, and rising sea temperatures. To protect these "rainforests of the ocean," the National Coral Reef Research Centre has been established at Port Blair Environment and Ecology, Majid Hussain, BIODIVERSITY, p.54.

Alongside corals, India possesses mangroves—salt-tolerant (halophytic) forests that thrive in intertidal zones. The Sundarbans in West Bengal represent the largest single block of tidal halophytic mangroves globally, famous for the Royal Bengal Tiger and species like Heritiera fimbriata Environment, Shankar IAS Academy, Aquatic Ecosystem, p.49. However, mangroves are found across all coastal states, including the Andaman and Nicobar Islands, where they serve as vital nurseries for fish and protection against tsunamis.

Reef Type	Key Characteristic	Primary Location in India
Fringing Reefs	Grow near the coastline around islands and continents.	Andaman Islands, Gulf of Mannar
Barrier Reefs	Separated from the shore by a deep lagoon.	Nicobar Islands, Lakshadweep
Atolls	Circular reefs enclosing a central lagoon.	Lakshadweep

Sources: Environment, Shankar IAS Academy, Aquatic Ecosystem, p.49, 51; Environment and Ecology, Majid Hussain, BIODIVERSITY, p.52, 54; Geography of India, Majid Husain, Natural Vegetation and National Parks, p.53

6. Geographic Passages and Maritime Boundaries (exam-level)

Concept: Geographic Passages and Maritime Boundaries

7. Solving the Original PYQ (exam-level)

Now that you have mastered the physiographic layout of the Indian islands, you can see how the Bay of Bengal archipelago is structured as a submerged mountain chain. The key to solving this question lies in recognizing the latitudinal markers that define these island clusters. As explained in INDIA PHYSICAL ENVIRONMENT, Geography Class XI (NCERT 2025 ed.), the entire chain is broadly divided into the Andaman group in the north and the Nicobar group in the south. The 10° Channel, named because it lies directly on the 10-degree line of latitude north of the equator, serves as the distinct 150 km-wide waterbody separating these two primary clusters.

To arrive at the correct answer, (B) 10° channel, you must distinguish between macro-level boundaries and micro-level passages. UPSC often uses proximity traps like Duncan Passage, which is a common point of confusion; however, that passage separates South Andaman from Little Andaman within the same group, rather than separating the two major clusters. Similarly, the Coco Channel is a boundary separating the Andamans from Myanmar's territory, while the Sombrero Channel is located within the Nicobar group itself. By visualizing the map from north to south, as outlined in Geography of India, Majid Husain, you can systematically eliminate these internal or international channels to identify the 10-degree line as the definitive divide between the Andaman and Nicobar Islands.