United Nations Convention on the Law of the Sea (UNCLOS)

What it is

The United Nations Convention on the Law of the Sea, adopted in 1982, is the primary international agreement that defines how countries use the oceans.

It is often called the “Constitution of the Oceans.”

Objectives

• Define maritime boundaries

• Ensure freedom of navigation

• Regulate use of ocean resources

• Protect marine environment

• Resolve maritime disputes

Key institutions created under UNCLOS

• International Tribunal for the Law of the Sea

• International Seabed Authority

• Commission on the Limits of the Continental Shelf

⚠️ Important Prelims fact:

The United States has not ratified UNCLOS, though it follows many of its rules.

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2. Maritime Zones under UNCLOS

Countries have different rights in different ocean zones.

Territorial Sea

• Extends 12 nautical miles from a country’s coastline.

• The coastal state has full sovereignty over this area.

Foreign ships may pass through it under innocent passage.

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Contiguous Zone

• Extends up to 24 nautical miles from the baseline.

• The coastal state can enforce laws related to:

  • Customs

  • Immigration

  • Sanitation

  • Security

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Exclusive Economic Zone (EEZ)

The Exclusive Economic Zone extends 200 nautical miles from the coastline.

Rights of the coastal state include:

• Exploration of marine resources

• Fishing rights

• Oil and gas extraction

• Energy production (wind, tidal)

However:

• Other states still enjoy freedom of navigation and overflight.

Example:

India’s EEZ extends 200 nautical miles into the Indian Ocean.

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Continental Shelf

Countries also have rights over the seabed and subsoil of their continental shelf.

This may extend beyond 200 nautical miles if geological conditions permit, subject to approval by the Commission on the Limits of the Continental Shelf.

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3. Innocent Passage

The Innocent Passage allows foreign ships to travel through a country’s territorial sea without seeking permission.

However, the passage must be peaceful and not threaten the security of the coastal state.

Activities that make passage non-innocent include:

• Weapons testing

• Military exercises

• Espionage

• Fishing

• Pollution

Countries may temporarily suspend innocent passage for security reasons.

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4. Freedom of Navigation

UNCLOS guarantees freedom of navigation on the high seas.

This means:

• Ships of all states may sail freely

• No country can claim sovereignty over international waters

This principle is often invoked by major naval powers such as the United States during Freedom of Navigation Operations (FONOPs).

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5. Naval Warfare Rules

UNCLOS mainly governs peacetime maritime law, but during armed conflict, the law of naval warfare also applies.

Important principles include:

Legitimate Targets

Warships belonging to an enemy state are considered legitimate military targets.

Example:

An Iranian warship could be targeted by an adversary during conflict.

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Neutral Shipping Protection

Merchant ships of neutral states should not be attacked unless they assist enemy forces.

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Blockades

A country may impose a naval blockade during war to prevent enemy trade.

But blockades must:

• Be declared publicly

• Apply equally to all ships

• Not block humanitarian aid

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6. Search and Rescue Obligations

Ships and coastal states must help people in distress at sea under international maritime law.

Countries cooperate through organisations such as the International Maritime Organization.

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7. Why Maritime Law Matters for India

For India, maritime law is crucial because:

• 90% of India’s trade by volume moves by sea

• India has a 7,500 km coastline

• India has a large Exclusive Economic Zone

These laws affect:

• Energy security

• Maritime disputes

• Naval operations

• Resource exploration

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✅ UPSC Tip:

Many questions link UNCLOS + Indian Ocean geopolitics + maritime disputes (South China Sea).

Example Mains question theme:

“Discuss the significance of UNCLOS in ensuring freedom of navigation and maritime security.”