Indian Coastline & Islands — Andaman & Nicobar, Lakshadweep, Coastal Ecosystems & Blue Economy

Overview

India has a vast coastline stretching across 9 coastal states and 4 Union Territories, flanked by the Arabian Sea, the Bay of Bengal, and the Indian Ocean. The country's two major island groups — Andaman & Nicobar in the Bay of Bengal and Lakshadweep in the Arabian Sea — are strategically vital for maritime security and rich in biodiversity. India's blue economy potential, anchored by the Sagarmala programme and the Deep Ocean Mission, is a growing focus for UPSC Mains (GS-I and GS-III).

Exam Strategy: For Prelims, focus on India's coastline length, state-wise ranking, island counts, Barren Island (only active volcano), Lakshadweep's coral atolls, and coral reef locations in India. For Mains, prepare topics on blue economy, Sagarmala, CRZ regulations, and the strategic significance of Andaman & Nicobar Islands (Tri-Service Command, proximity to Strait of Malacca).

India's Coastline — Key Facts

Key Fact: The 2024 revision from 7,516.6 km to 11,098.8 km (a 47.6% increase) is due to improved measurement technology and the addition of approximately 1,389 islands/islets that were not included in the 1970s survey. This reflects the coastline paradox — the measured length of a coastline increases as the measurement scale becomes finer (mathematically formalised by Benoit Mandelbrot in 1967). For UPSC, both figures may be tested — note the traditional figure (7,516.6 km) in older references and the revised figure (11,098.8 km) in current affairs.

State-wise Coastline Length (Traditional)

Prelims Tip: Gujarat has the longest mainland coastline among all Indian states (~1,600 km). Among all entities including UTs, Andaman & Nicobar has the longest coastline.

Andaman & Nicobar Islands

Geography and Key Facts

Barren Island — India's Only Active Volcano

Protected Tribes

Strategic Importance

Exam Tip: The Andaman & Nicobar Command (ANC) was India's first and remains its only tri-service theatre command. It was established in 2001 at Port Blair (now Sri Vijaya Puram). Its strategic location near the Strait of Malacca — through which ~25% of global trade passes — makes these islands critical for India's maritime security and Indo-Pacific strategy.

Lakshadweep Islands

Geography and Key Facts

Coral Atolls

All Lakshadweep islands are coral atolls — ring-shaped coral reefs enclosing a shallow lagoon. They are formed by coral growth on top of submerged volcanic peaks. The islands are low-lying (highest point ~5 m above sea level), making them extremely vulnerable to sea-level rise.

PSSA Status

Lakshadweep has been designated a Particularly Sensitive Sea Area (PSSA) by the International Maritime Organisation (IMO), recognising its ecological significance and vulnerability to maritime activities.

Marine Biodiversity

Coastal Ecosystems

Mangroves

Mangroves are salt-tolerant trees and shrubs growing in the intertidal zones of tropical and subtropical coastlines. They serve as natural coastal buffers, nurseries for marine life, and carbon sinks.

Coral Reefs in India

Coral reefs are found in four major regions of India:

Key Fact: Coral reefs are NOT found in the Sundarbans — the high sediment load, turbidity, and brackish water from the Ganga-Brahmaputra delta make conditions unsuitable for coral growth. This is a frequently tested Prelims fact (UPSC 2014).

Other Coastal Ecosystems

Blue Economy

India's blue economy encompasses all economic activities related to oceans, seas, and coastal areas — including fisheries, shipping, tourism, offshore energy, and deep-sea mining.

India's Blue Economy Vision

Sagarmala Programme

Mains Relevance: The Sagarmala programme aims to reduce logistics costs by shifting cargo movement from road to coastal shipping and inland waterways. India's logistics cost (~14% of GDP) is significantly higher than global average (~8%). Port modernisation and coastal economic zones are key strategies to improve India's export competitiveness.

Coastal Regulation Zone (CRZ) — Brief Overview

Coastal Erosion

Key Fact: India loses approximately 45% of its non-rocky coastline to erosion, according to the National Centre for Coastal Research (NCCR). The most affected states include Kerala, West Bengal, Puducherry, and parts of Tamil Nadu and Odisha.

Frequently Asked Questions (Prelims Pattern)

Important Channels, Straits, and Water Bodies Around India

Prelims Tip: Remember the degree channels — Ten Degree Channel (Andaman-Nicobar), Nine Degree Channel (within Lakshadweep), Eight Degree Channel (Lakshadweep-Maldives). These are frequently tested in both Prelims and mapping questions.

Major Ports of India

India has 12 major ports (under central government) and over 200 minor/intermediate ports (under state governments).

Key Terms for Quick Revision

Sources: Ministry of Ports, Shipping and Waterways (Sagarmala); PIB (pib.gov.in — Deep Ocean Mission, coastline revision); Official Lakshadweep Portal (lakshadweep.gov.in); Wikipedia (Andaman and Nicobar Islands, Lakshadweep, Barren Island); NCCR; Insights on India (coastline revision 2025); India State of Forest Report 2023; UNDP India (coral reefs).