Coastline and the island territories

Detail

1. How long is India's coastline?

• The Peninsula sets the shape. Peninsular India juts south into the Indian Ocean. It has the Arabian Sea to the west and the Bay of Bengal to the east. This is why India has such a long coast.
• The NCERT figure:
• Mainland: 6,100 km.

• With the islands: 7,516.6 km (≈7,517 km). This adds the Andaman and Nicobar Islands in the Bay of Bengal and Lakshadweep in the Arabian Sea.

• The revised official figure (2025): 11,098.81 km, up from 7,516.6 km [2][3].

• Who measured it: the National Hydrographic Office (NHO), working with the Survey of India (SoI) [3]. The remeasurement ran in 2023–24.
• How: they used modern GIS software (Geographic Information System: computer software that stores and measures map data). They traced the coast on high-resolution data of the High-Water Line (HWL) from the latest surveys. The HWL is the line the sea reaches at high tide [3]. The work used finer 1:250,000 digital maps.
• Who approved it: first the Coastal Protection and Development Advisory Committee (CPDAC), after every coastal state and UT agreed. Then the Ministry of Ports, Shipping and Waterways made it official in a circular dated 29 April 2025 [3].
• (NCERT: 7,516.6 km with islands; 6,100 km mainland.)

2. Why the figure jumped by about 48%: the coastline paradox

• Coastline paradox: the more closely you measure a wiggly coast, the longer it gets. On a finer map scale, the measured length goes up.
• How it worked for India:
• Old method: the 7,516.6 km figure came from coarse small-scale maps of the 1970s. On those maps a bay or creek looks like a straight line.
• New method: finer 1:250,000 digital maps showed the edges of bays, creeks and estuaries. An estuary is the wide mouth of a river where it meets the sea. The new maps also counted more small islands.

• Result: the same coast now measures about 3,582 km more, an increase of about 48%.

• India's territory did not change. Only the measuring method improved.

• The same effect worldwide: Britain's coast is the textbook example, and Norway's coast with its many fjords behaves the same way.

3. NCERT books give different figures

NCERT book	Coastline figure
Class 11, "India – Location"	6,100 km mainland; 7,516.6 km with islands
Class 7 (older book, "India's Amazing Coastlines")	"over 7,500 km"
Class 7 (new edition)	"approximately 11,100 km"

• Exam tip: for current-fact questions, use 11,098.81 km. If a question says "as per NCERT Class 11", the answer may be 7,516.6 km. Read the question carefully.

4. Coastal states and Union Territories

• 9 coastal states. From west to east along the coast:
• Gujarat → Maharashtra → Goa → Karnataka → Kerala (on the Arabian Sea).
• Tamil Nadu → Andhra Pradesh → Odisha → West Bengal (on the Bay of Bengal).

• Tamil Nadu's southern tip, near Kanniyakumari, faces the open Indian Ocean.

• 4 coastal UTs:

• Dadra and Nagar Haveli and Daman and Diu (Arabian Sea side).
• Puducherry (mostly on the Coromandel coast in the Bay of Bengal; Mahe is on the Malabar coast in Kerala).
• Lakshadweep (Arabian Sea).
• Andaman and Nicobar Islands (Bay of Bengal).

5. Who has the longest coast? (Revised 2025 figures)

Unit	Revised length (2025)	Note
Andaman and Nicobar Islands (UT)	3,083.50 km [2]	Longest of all states and UTs
Gujarat (state)	2,340.62 km [2]	Longest among states; biggest increase (+1,125.9 km) [3]
Tamil Nadu (state)	1,068.69 km [2]	Long east and south coast
Lakshadweep (UT)	144.80 km [2]	Small coral islands
India total	11,098.81 km [2]	(NCERT: 7,516.6 km)

• Gujarat has the longest coast among states. It is cut deeply by the Gulf of Kachchh and the Gulf of Khambhat. These gulfs, with their many creeks, added the most length in the recount [3].
• Andaman and Nicobar has the longest coast among UTs. Its revised coast (3,083.50 km) is longer than Gujarat's [2]. Hundreds of islands each add their own shoreline.

6. What a long coastline means for India

• Gains:
• Ports and trade: most of India's foreign trade by volume goes by sea.
• Fisheries: coastal and deep-sea fishing supports millions of livelihoods, mostly in Kerala, Gujarat, Tamil Nadu, Andhra Pradesh and Maharashtra.
• A large EEZ. EEZ means Exclusive Economic Zone: the sea up to 200 nautical miles from the coast, where a country alone may use the fish, oil, gas and minerals (under UNCLOS, the UN Convention on the Law of the Sea). India's EEZ covers about 2.02 million sq km [4].
• Offshore oil and gas: for example, Mumbai High in the Arabian Sea and the Krishna–Godavari basin in the Bay of Bengal.
• Milder coastal climate:
  • The sea heats and cools more slowly than land.
  • So coastal places have a small gap between summer and winter temperatures. This is called a maritime (equable) climate.
  • Mumbai is an example. Delhi, far inland, has a continental (extreme) climate.

• Tourism: beaches and islands such as Goa, Kerala, Andaman and Lakshadweep.

• Risks:

• Cyclones:
  • The Bay of Bengal is warm and shallow, and cyclones form over it often.
  • They strike Odisha, Andhra Pradesh, West Bengal and Tamil Nadu.
  • Strong winds, a storm surge (a sudden rise of sea water pushed inland by the storm) and heavy rain follow.
• Tsunamis:
  • An undersea earthquake suddenly lifts the sea floor.
  • Huge waves spread out across the ocean.
  • The 2004 Indian Ocean tsunami hit Tamil Nadu and the Andaman and Nicobar Islands.
• Sea-level rise:
  • Global warming expands sea water and melts ice.
  • The sea creeps inland.
  • Low coasts and low islands are most at risk, such as the Sundarbans (West Bengal) and Lakshadweep.

7. The island territories (one line each)

Feature	Andaman and Nicobar Islands	Lakshadweep
Sea	Bay of Bengal	Arabian Sea
Number of islands	about 572	about 36
Latitude	6°–14°N	8°–12°N
Longitude	92°–94°E	71°–74°E
Type	Mostly hilly; the tops of an undersea mountain chain	Low coral islands (built by tiny sea animals called coral polyps)
Key marker	Ten Degree Channel separates the Andaman group from the Nicobar group; Indira Point (Great Nicobar) is India's southernmost point	Nine Degree Channel separates Minicoy from the main group; Eight Degree Channel separates Minicoy from the Maldives
Coast (revised 2025)	3,083.50 km [2]	144.80 km [2]

• The islands enlarge the EEZ a lot. Each island creates its own circle of EEZ around it. So the Andaman and Nicobar Islands give India a big block of EEZ far out in the eastern Bay of Bengal. Lakshadweep does the same in the Arabian Sea.
• More sea area may come. Once India's continental shelf (the shallow, underwater edge of a continent) is mapped under UNCLOS, India's sea area could grow by about another 1 million sq km [4].

Prelims Hooks

• India's coastline (revised, MoPSW circular of 29 April 2025): 11,098.81 km. The old figure was 7,516.6 km, and the mainland alone was 6,100 km (NCERT).
• Who remeasured it: the National Hydrographic Office (NHO) with the Survey of India. They used GIS and the High-Water Line. Approval came from the CPDAC.
• The increase came from the coastline paradox. Finer maps traced more creeks, bays and estuaries. No new territory was added.
• Trap: the Andaman and Nicobar Islands (3,083.50 km) now have a longer coast than Gujarat (2,340.62 km). Gujarat is longest among states only.
• Gujarat had the biggest gain in the recount: +1,125.9 km.
• Coastal states, west to east: Gujarat, Maharashtra, Goa, Karnataka, Kerala, Tamil Nadu, Andhra Pradesh, Odisha, West Bengal. That makes 9 states and 4 coastal UTs.
• Coastal UTs: DNH and Daman and Diu, Puducherry, Lakshadweep, Andaman and Nicobar. Trap: Ladakh, J&K, Delhi and Chandigarh are landlocked.
• Channels, north to south:
• In the Arabian Sea: Nine Degree Channel (between Lakshadweep and Minicoy), then Eight Degree Channel (between Minicoy and the Maldives).

• In the Bay of Bengal: the Ten Degree Channel lies between the Andaman and Nicobar groups.

• India's EEZ: about 2.02 million sq km. Mapping the continental shelf under UNCLOS may add about 1 million sq km.

• Lakshadweep: about 36 islands, all coral. Andaman and Nicobar: about 572 islands at 6°–14°N.

Mains Points

• Coastline paradox and why it matters (GS-I): the jump from 7,516.6 km to 11,098.81 km shows that a measured length depends on map scale. A longer official coast changes how far CRZ (Coastal Regulation Zone: the strip along the coast where building is controlled) rules reach. It also changes coastal-security planning, coastal-erosion maps and the funds given to coastal states.
• Long coast as a strength (GS-III): India has about 11,099 km of coast and an EEZ of about 2.02 million sq km. This supports sea trade through ports (the Sagarmala port programme), fisheries, offshore oil and gas (Mumbai High, the KG basin) and the Blue Economy (income from ocean resources such as fishing, shipping, seabed minerals and tourism).
• Long coast as a risk (GS-III, disasters): the east coast is open to cyclones. The Andaman and Nicobar Islands lie near earthquake zones and are at risk from tsunamis. The Sundarbans and Lakshadweep face sea-level rise. Responses include tsunami and storm-surge warnings from INCOIS, mangrove shelterbelts (belts of mangrove trees that soften waves) and coastal zone management plans.
• Islands and strategy (GS-I/III): the Andaman and Nicobar Islands lie close to the Strait of Malacca and Lakshadweep lies close to the Nine and Eight Degree Channels. Both give India a strong position on major Indian Ocean sea lanes and add large EEZ blocks. India's joint tri-service Andaman and Nicobar Command is based there [4].