United Nations Convention on the Law of the Sea

Also called: UNCLOS · Topic: India: Location, Size, Extent and Divisions · NCERT: Beyond NCERT

Meaning

The United Nations Convention on the Law of the Sea (UNCLOS) is the world treaty that sets the rules for using the oceans and their resources. It divides the sea into zones: territorial sea, contiguous zone, exclusive economic zone (EEZ), continental shelf, high seas and the deep seabed beyond national limits (the Area). It was adopted in 1982 at Montego Bay (Jamaica), came into force in 1994, and India ratified it in 1995.

It matters because it decides how far India's rights reach into the sea. These rights cover fish, oil and gas, and deep-sea minerals. UNCLOS is also the rulebook India uses to settle sea borders with its neighbours.

Explanation

How the zones are measured

• 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 [5].

• Unit used: the nautical mile (nm)

• 1 nautical mile = 1.852 km = one minute of latitude (1/60 of a degree).
• So 60 nm = 1° of latitude. A navigator can read sea distance straight off a chart.

• An ordinary land mile (statute mile) is only about 1.6 km.

• Where the zones sit in the treaty:

• Part II: territorial sea and contiguous zone.
• Part V: EEZ.
• Part VI: continental shelf.

The zones, from the coast outwards

Zone	Outer limit (from baseline)	Approx. km	Nature of the coastal state's rights
Territorial sea	12 nm	22.2	Full sovereignty over water, seabed, subsoil and airspace, subject to innocent passage
Contiguous zone	24 nm	44.4	Control for customs, fiscal, immigration, sanitary and security purposes
EEZ	200 nm	370.4	Sovereign rights over living and non-living resources
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 (0–12 nm): India treats this belt like its own land.
• Innocent passage: foreign ships may sail through without stopping, as long as they do not harm India's peace, good order or security.
• A cargo ship sailing quietly past the Gujarat coast is in innocent passage. A ship that fishes, spies or pollutes is not.

• The right covers ships only. Foreign aircraft need permission to fly over this belt.

• Contiguous zone (12–24 nm): here India has policing powers only, not sovereignty [5].

• Customs stops smuggled goods. Fiscal powers collect taxes and duties. Immigration powers stop illegal entry of people. Sanitary powers protect health, for example through quarantine. Security powers protect the country.

• Why it exists: a smuggler can be caught before reaching the 12 nm line.

• EEZ (up to 200 nm): only India may explore, use, conserve and manage the resources here [5].

• Living resources: fish, prawns and other marine life.
• Non-living resources: oil, natural gas and minerals.
• India also controls energy from wind, waves and currents.

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

• Continental shelf: in law, this is the seabed and subsoil beyond the territorial sea. It is the natural prolongation (the underwater continuation) of the land. It reaches either the outer edge of the continental margin (where the continent's rock ends and the deep ocean floor begins) or 200 nm, if the margin ends before that [5].

• Extended continental shelf: if the margin goes beyond 200 nm, a state may claim seabed rights up to 350 nm.
• First it must send scientific proof to the CLCS (Commission on the Limits of the Continental Shelf), the UN expert body that checks such claims.
• Shelf rights cover only the seabed and below it. The water above the shelf beyond 200 nm is high seas.

Beyond national limits

• High seas: all the water beyond every country's EEZ. It is open to all states, and 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" (they belong to all humanity, not to one country).
• The International Seabed Authority (ISA), based in Kingston, Jamaica, manages it.

How UNCLOS fits with India's own law

• India passed the Maritime Zones Act before UNCLOS existed. It is Act No. 80 of 1976. It was enacted on 25 August 1976 and came into force on 15 January 1977 [5].
• That Act already used the same limits: 12 nm, 24 nm and 200 nm [5].
• When India ratified UNCLOS in 1995, its law already matched the treaty.

Where it occurs

• Montego Bay, Jamaica: where UNCLOS was adopted in 1982.
• Kingston, Jamaica: headquarters of the ISA, which manages the deep seabed under UNCLOS.
• India's EEZ: spreads over more than 2.2 million sq km [1]. That is roughly two-thirds of India's land area of about 3.28 million sq km.
• Other sources give about 2.02 million sq km or about 2.37 million sq km. The figures differ because they are calculated in different ways.

• Andaman and Nicobar Islands (Bay of Bengal) and Lakshadweep (Arabian Sea): each island makes its own 200 nm circle, so the island groups add a large share of the EEZ.

• Mumbai High (Arabian Sea, off the Maharashtra coast): offshore oil and gas from the continental shelf and EEZ.

• Central Indian Ocean Basin (CIOB): lies in the Area. India holds polymetallic nodule exploration rights here under a contract with the ISA.
• Polymetallic nodules are potato-sized lumps on the deep ocean floor that contain many metals.

• Allotted area: 75,000 sq km. First estimates: about 380 million metric tonnes of nodules, holding copper, nickel, cobalt and manganese [1].

• Arabian Sea (extended shelf 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 [6].
• On 3 April 2025, India filed an amended partial submission for the Western Offshore Region, covering the Central Arabian Sea and the Northern Arabian Sea [6][7].
• The CLCS placed it on the agenda of its 64th session (New York, 7 July – 8 August 2025) [7].

• Myanmar, Bangladesh, Oman and Pakistan have sent the UN notes about India's submissions (2009–2025) [6].

• Bay of Bengal (India–Bangladesh): an Arbitration Tribunal under Annex VII of UNCLOS gave its award on 7 July 2014. The award is final and binding on both countries [4].

• The Permanent Court of Arbitration (The Hague) served as the registry, the office that handled the case.

Don't confuse with

• Maritime Zones Act 1976: this is India's own law (Act No. 80 of 1976) [5]. UNCLOS is the international treaty (1982). India's Act came first.
• Territorial sea vs EEZ: sovereignty ends at 12 nm. In the EEZ, India has only resource rights. Other states keep freedom of navigation, overflight and laying of cables and pipelines.
• CLCS vs ISA: the CLCS checks a country's claim to an extended continental shelf, up to 350 nm. The ISA (Kingston) manages the seabed beyond every country's shelf, which is the Area.
• High seas vs the Area: the high seas are the water beyond every EEZ. The Area is the seabed beyond every continental shelf, and its minerals are "common heritage of mankind".

Prelims Hooks

• UNCLOS: adopted 1982 at Montego Bay (Jamaica), in force 1994, ratified by India 1995. India's Maritime Zones Act (1976, in force 15 January 1977) came before it [5].
• 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 / the Area.
• Only the territorial sea gives full sovereignty, including the airspace. Trap: the contiguous zone gives only customs, fiscal, immigration, sanitary and security powers, with no sovereignty and no resource rights.
• 1 nautical mile = 1.852 km = one minute of latitude. 12 nm ≈ 22.2 km (NCERT: about 21.9 km). 200 nm ≈ 370.4 km.
• India's nodule site: Central Indian Ocean Basin, 75,000 sq km, under the ISA. Metals: Cu, Ni, Co, Mn [1].
• India–Bangladesh sea boundary: UNCLOS Annex VII tribunal award on 7 July 2014, with the PCA as registry [4]. Extended shelf claim to the CLCS: 11 May 2009, amended 3 April 2025 for the Arabian Sea [6].

Mains Points

• UNCLOS gives India a large sea resource base (GS-III):
• The EEZ of more than 2.2 million sq km [1] supports fisheries, coastal jobs and offshore oil (Mumbai High).
• India's ISA contract in the CIOB gives access to copper, nickel and cobalt, metals needed for batteries and the energy shift [1].

• The Deep Ocean Mission (Ministry of Earth Sciences, 2021–2026, ₹4,077 crore) is how India plans to use these resources [3]. It includes a manned submersible that carries three people to 6,000 m and a mining system for nodules at 6,000 m [1][2].

• India settles sea disputes peacefully under UNCLOS:

• India accepted the 2014 award with Bangladesh as final and binding [4].
• India filed its extended-shelf claims (2009 and 2025) with the CLCS [6].

• This supports a rules-based order in the Indian Ocean. Overlapping claims remain: Myanmar, Bangladesh, Oman and Pakistan have sent notes to the UN about India's submissions [6].

• Problems and policy response:

• Security: the Andaman and Nicobar Islands sit close to the Malacca Strait shipping route. Guarding the contiguous zone and EEZ against illegal fishing, smuggling and spying is a security task.
• Livelihood and environment: fishermen cross sea borders (for example with Sri Lanka in the Palk Bay), the EEZ is overfished, and deep-sea mining can harm marine life.
• Response: a balanced Blue Economy policy that uses the ocean's wealth and also protects the ocean.

Related concepts

• Maritime zones of India
• Territorial sea
• Exclusive economic zone

Read more

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