Maritime zones: territorial sea, contiguous zone, EEZ and continental shelf

Detail

1. How far India's sea limit goes: the nautical mile

• Territorial limit: India's territorial limit runs 12 nautical miles out to sea from the coast.

• 12 nm = about 22.2 km (12 × 1.852 km). (NCERT: about 21.9 km.)

• NCERT box: two kinds of mile

Unit	Length in inches	Length in km	Who uses it
Statute mile (the ordinary mile on land)	63,360 inches	about 1.6 km	road distances on land
Nautical mile (the mile used at sea)	72,960 inches	about 1.852 km	ships and aircraft

• Why ships and aircraft use the nautical mile:
• One nautical mile equals one minute of latitude. A minute is 1/60 of a degree.

• So a navigator can turn a distance on a chart straight into latitude. 60 nm = 1° of latitude.

• Quick conversions to remember:

• 12 nm ≈ 22.2 km
• 24 nm ≈ 44.4 km
• 200 nm ≈ 370.4 km
• 350 nm ≈ 648 km

2. The legal framework: India's law and UNCLOS

• Maritime Zones Act 1976: its full name is The Territorial Waters, Continental Shelf, Exclusive Economic Zone and Other Maritime Zones Act, 1976. It is Act No. 80 of 1976. It was enacted on 25 August 1976 and came into force on 15 January 1977 [6].

• India passed this law before UNCLOS existed. It already used the same limits: 12 nm, 24 nm and 200 nm [6].

• UNCLOS (United Nations Convention on the Law of the Sea): the world treaty that sets the rules for using the oceans and their resources.

• Adopted in 1982 at Montego Bay (Jamaica).
• Came into force in 1994.
• Ratified by India in 1995.

• The zones are set out in its Part II (territorial sea and contiguous zone), Part V (EEZ) and Part VI (continental shelf).

• Baseline: the official coastline from which every zone is measured.

• Normally it is the low-water line, the line the sea reaches at low tide.
• Each zone limit is a line on which every point is the stated distance from the nearest point of the baseline [6].

3. The four zones, from the coast outwards

Zone	Outer limit (from baseline)	Approx. km	Nature of India's rights
Territorial sea	12 nm	22.2	Full sovereignty over the water, seabed, subsoil and airspace, subject to innocent passage
Contiguous zone	24 nm	44.4	Control for customs, fiscal (tax), immigration, sanitary (health) and security purposes
Exclusive economic zone (EEZ)	200 nm	370.4	Sovereign rights over living and non-living resources; other states keep freedom of navigation and overflight
Continental shelf	200 nm, or the outer edge of the continental margin up to 350 nm	370–648	Rights over seabed and subsoil resources

Territorial sea

• Territorial sea: the belt of sea next to the coast, up to 12 nm. India treats it like its own land territory.
• India controls the water, seabed, subsoil and the airspace above.
• Innocent passage: foreign ships may pass through without stopping, as long as they do not harm India's peace, good order or security.
• Example: a cargo ship sailing quietly past the Gujarat coast is in innocent passage.
• A ship that fishes, spies or pollutes is not.
• This right covers ships only. Foreign aircraft need permission to fly over the territorial sea.

Contiguous zone

• Contiguous zone: the belt of sea just beyond the territorial sea, between 12 nm and 24 nm from the baseline [6].
• India does not have full sovereignty here. It has policing powers only:
• customs: to stop smuggling of goods;
• fiscal: to collect taxes and duties;
• immigration: to stop illegal entry of people;
• sanitary: to protect health, for example by quarantine;

• security: to protect the country.

• Why it exists: a smuggler can be caught before reaching the 12 nm line. India does not have to wait until the smuggler is already inside its waters.

Exclusive economic zone (EEZ)

• EEZ: the area beyond and next to the territorial sea, up to 200 nm from the baseline [6].
• India has sovereign rights: only India may explore, use, conserve and manage the resources there.
• Living resources: fish, prawns and other marine life.
• Non-living resources: oil, natural gas and minerals.

• India also controls other economic uses, such as energy from wind, waves and currents.

• Other states keep freedom of navigation and overflight. They may also lay submarine cables and pipelines.

• Trap: the EEZ is not sovereign territory. Sovereignty ends at 12 nm.

Continental shelf

• Continental shelf (legal meaning): the seabed and subsoil under the sea beyond the territorial sea. It continues as the natural prolongation (the underwater continuation) of the land territory up to:
• the outer edge of the continental margin (where the continent's rock ends and the deep ocean floor begins); or

• 200 nm from the baseline, if the margin ends before that [6].

• Extended continental shelf: if the margin goes beyond 200 nm, a state may claim seabed rights up to a maximum of 350 nm. It must first send scientific proof to the CLCS (Commission on the Limits of the Continental Shelf: the UN expert body that checks such claims).

• India's claim:
• India made a partial submission to the CLCS on 11 May 2009. It kept the right to file a separate claim later for the southern Bay of Bengal [7].
• On 3 April 2025, India filed an amended partial submission. It covered the Western Offshore Region, in both the Central Arabian Sea and the Northern Arabian Sea [7][8].
• The CLCS placed India's amended submission on the agenda of its 64th session (New York, 7 July – 8 August 2025) [8].

• Myanmar, Bangladesh, Oman and Pakistan have sent the UN notes about India's submissions (2009–2025). This shows that neighbours' claims overlap with India's [7].

• Difference from the EEZ: shelf rights cover only the seabed and below it. The water above the shelf beyond 200 nm is the high seas.

• (The continental shelf as a physical landform is covered in ocean-relief-temperature-salinity.)

4. Beyond national limits: the high seas and the Area

• High seas: all the water beyond every country's EEZ. It is open to all states. No country owns it.
• International Seabed Area ("the Area"): the seabed beyond every country's continental shelf.
• UNCLOS calls its minerals the "common heritage of mankind".

• The International Seabed Authority (ISA), based in Kingston, Jamaica, manages it.

• India's rights in the Area:

• India holds polymetallic nodule exploration rights in the Central Indian Ocean Basin (CIOB), under a contract with the ISA.
• Polymetallic nodules: potato-sized lumps on the deep ocean floor. They contain many metals.
• Allotted area: 75,000 sq km [2].
• First estimates: about 380 million metric tonnes of nodules, holding copper, nickel, cobalt and manganese [2].
• (Link: mineral-resources-india.)

5. Size of India's EEZ

• Area: India's EEZ spreads over more than 2.2 million sq km [2].
• Other sources give about 2.02 million sq km or about 2.37 million sq km (23.7 lakh sq km).

• The range is wide because the figures are calculated in different ways.

• Compared with land: India's land area is about 3.28 million sq km. So the EEZ equals roughly two-thirds of the land area.

• The islands add a large share:
• Andaman and Nicobar Islands in the Bay of Bengal: each island creates its own 200 nm circle, so a long island chain gives a very large EEZ.
• Lakshadweep in the Arabian Sea does the same.
• Together they give India sea rights far beyond the mainland coast.

6. Uses of the zones

Use	Where	Zone involved
Fisheries	All along the west and east coasts; around the islands	Territorial sea and EEZ
Offshore oil and gas	Mumbai High, in the Arabian Sea off the Maharashtra coast	Continental shelf / EEZ
Deep-sea minerals	Central Indian Ocean Basin	International Seabed Area (under the ISA)
Ocean science and mapping	Deep Ocean Mission	EEZ and beyond

• Deep Ocean Mission (DOM):
• Approved in 2021.
• Run by the Ministry of Earth Sciences.
• Budget: ₹4,077 crore for five years (2021–2026) [4].
• Main parts:
  • a manned submersible (a small deep-diving craft) that carries three people to 6,000 m depth [2][3];
  • an integrated mining system to mine polymetallic nodules from 6,000 m in the Central Indian Ocean [2][3].

7. Settling sea borders

• Neighbouring countries' zones often overlap. They have to be divided by agreement or by a court.
• India–Bangladesh (Bay of Bengal):
• An Arbitration Tribunal set up under Annex VII of UNCLOS gave its award on 7 July 2014 [5].
• The Permanent Court of Arbitration (The Hague) acted as the registry for the case.
• The award is final and binding on both countries. It settled the sea border between them [5].

• Result: both countries can now use the resources of that part of the Bay of Bengal. The old dispute had held this back [5].

• Other neighbours (Sri Lanka, Maldives, Myanmar): see india-neighbours.

Prelims Hooks

• 1 nautical mile = 1.852 km = one minute of latitude. 1 statute mile ≈ 1.6 km (63,360 inches). A nautical mile is 72,960 inches.
• Territorial sea = 12 nm ≈ 22.2 km (NCERT: 21.9 km). It is the only zone with full sovereignty, including the airspace.
• Order from the baseline outwards: territorial sea (12 nm) → contiguous zone (24 nm) → EEZ (200 nm) → extended continental shelf (up to 350 nm) → high seas / International Seabed Area.
• Contiguous zone powers: customs, fiscal, immigration, sanitary and security. Trap: the zone gives no sovereignty and no rights over resources.
• EEZ trap: other states keep freedom of navigation, overflight and laying of cables and pipelines. Only resource rights belong to India.
• India's Maritime Zones Act came before UNCLOS: Act No. 80 of 1976, in force on 15 January 1977 [6]. UNCLOS: adopted 1982 (Montego Bay), in force 1994, ratified by India 1995.
• Extended shelf claim: filed with the CLCS on 11 May 2009 and amended on 3 April 2025 for the Arabian Sea [7].
• India's polymetallic nodule site: Central Indian Ocean Basin, 75,000 sq km, under the ISA. Metals: Cu, Ni, Co, Mn [2].
• Deep Ocean Mission: Ministry of Earth Sciences, 2021–26, ₹4,077 crore. Manned submersible goes to 6,000 m [4][3].
• India–Bangladesh sea boundary: UNCLOS Annex VII tribunal award, 7 July 2014, with the PCA as registry [5].

Mains Points

• The EEZ is a resource base (GS-III): the EEZ, more than 2.2 million sq km [2], about two-thirds of India's land area, supports:
• fisheries and coastal jobs;
• offshore oil (Mumbai High);
• deep-sea minerals (copper, nickel and cobalt from CIOB nodules), which are needed for batteries and the energy shift.

• The Deep Ocean Mission is the way India is trying to unlock these resources [2][4].

• The islands matter for strategy:

• The Andaman and Nicobar Islands and Lakshadweep add a large share of the EEZ.
• The Andaman and Nicobar Islands sit close to the Malacca Strait shipping route.

• Guarding these waters against illegal fishing, smuggling and spying (the job of the contiguous zone and the EEZ) is a security task.

• Sea borders are settled peacefully under international law:

• The 2014 India–Bangladesh award was accepted as final and binding [5].
• The extended-shelf claims (2009 and 2025) were sent to the CLCS [7].
• Both show India following UNCLOS. This supports a rules-based order in the Indian Ocean.

• Overlapping claims still remain. Myanmar, Bangladesh, Oman and Pakistan have sent notes to the UN about India's claims [7].

• Problems:

• fishermen crossing sea borders, for example with Sri Lanka in the Palk Bay;
• overfishing in the EEZ;
• the environmental risk of deep-sea mining for marine life.
• These need a balanced Blue Economy policy: using the ocean's wealth while protecting the ocean.