UPSC CSE Prelims
Islands of India Previous Year Questions (PYQs)

Detailed Explanation:

Answer: Option 4 — 1 only

Only Statement 1 is correct. Barren Island is indeed India's only active volcano, located in the Andaman Sea within Indian territory. Statement 2 is incorrect because Barren Island lies approximately 135-140 km east of Port Blair, not Great Nicobar, which is much further south. Statement 3 is also incorrect as the volcano has erupted multiple times after 1991, including in 1994-95, 2005-07, and most recently in 2017, proving it has not remained inactive.

✅ Statement 1 – Correct: Barren Island is the only confirmed active volcano in India, located in the Andaman Sea, part of the Union Territory of Andaman and Nicobar Islands.
❌ Statement 2 – Incorrect: Barren Island is located approximately 135-140 km east of Port Blair, not Great Nicobar; Great Nicobar is the southernmost island located much further south (around 7°N) while Barren Island is at approximately 12.2°N.
❌ Statement 3 – Incorrect: The volcano has not remained inactive since 1991; it has erupted several times including in 1994-95, 2005-07, and as recently as 2017.

📝 Short Notes: Barren Island Volcano

• Location: Barren Island is located in the Andaman Sea, approximately 135-140 km east of Port Blair in the Andaman and Nicobar Islands.
• Only Active Volcano: It is the only confirmed active volcano in South Asia and India.
• Part of Volcanic Arc: Barren Island is part of the volcanic arc chain extending from Sumatra to Myanmar, formed due to the subduction of the Indian Plate beneath the Burmese Plate.
• Eruption History: After lying dormant for nearly 150 years, it erupted in 1991, and has since shown activity in 1994-95, 2005-07, and 2017.
• Uninhabited: The island is uninhabited due to volcanic activity and is restricted for tourism, though diving expeditions are sometimes permitted.
• Geographical Coordinates: Approximately 12.2°N latitude and 93.9°E longitude.

Detailed Explanation:

Answer: Option 1 — Sumatra

Sumatra is the geographically closest island to Great Nicobar, separated by the Great Channel (also known as the Six Degree Channel or Strait of Sumatra). The distance between the southernmost point of Great Nicobar and the northern tip of Sumatra (Aceh province, Indonesia) is approximately 145–150 km.

In contrast, Sri Lanka is located about 1,200 km to the west of the Nicobar Islands across the Bay of Bengal. Java is situated to the southeast of Sumatra, at a distance of over 1,500 km from Great Nicobar. Borneo is positioned much further east in the Malay Archipelago, making it the most distant among all options. Therefore, Sumatra is the correct answer.

Detailed Explanation:

The Ten Degree Channel is located at approximately 10°N latitude in the Bay of Bengal and separates Little Andaman Island (southernmost of Andaman group) from Car Nicobar Island (northernmost of Nicobar group).

Other channels: Great Channel (separates Nicobar from Sumatra), Eight Degree Channel (separates Minicoy from Maldives), Nine Degree Channel (separates Minicoy from rest of Lakshadweep), and Sunda Strait (separates Sumatra from Java).