Answer
When a marine oil pollution incident occurs, a Coastal State operates under a framework of international law (primarily UNCLOS and MARPOL) and domestic legislation (in India, the Merchant Shipping Act, 2025).
Under these frameworks, the duties and rights of a Coastal State following an oil pollution incident generally fall into three phases: Prevention/Response, Enforcement, and Compensation.
1. Emergency Response and Mitigation
The primary duty of a Coastal State is to protect its marine environment and resources.
Contingency Plan Activation: The coastal state must immediately activate its National Oil Spill Disaster Contingency Plan (NOS-DCP), deploying specialized response craft, containment booms, skimmers, and recovery teams to the spill site.
Intervention: Under the International Convention Relating to Intervention on the High Seas in Cases of Oil Pollution Casualties, 1969, a Coastal State has the right to take necessary measures beyond its territorial sea to protect its coastline from pollution or the threat of pollution following a maritime casualty.
Coordination: The State acts as the lead coordinator for emergency response, which includes mobilizing resources for salvage, lightering (de-fueling/de-ballasting), and containment to mitigate environmental impact.
Promulgate Navigational Warnings: Broadcast continuous maritime safety information via NAVTEX or satellite channels to warn surrounding shipping traffic of the slick coordinates and navigation hazards.
2. Monitoring and Enforcement Jurisdiction
Environmental Monitoring & Mapping: Deploy aerial surveillance, coast guard flights, and oceanographic tracking models to continuously plot the spill's drift velocity, thickness, and projected shoreline impact zones.
The Coastal State exercises jurisdiction based on the maritime zone in which the incident occurs (Territorial Sea, EEZ, or High Seas):
Territorial Sea: The Coastal State has full sovereignty. If a foreign ship commits a violation of laws implementing MARPOL within the territorial sea, the State can inspect, detain, and institute proceedings.
Exclusive Economic Zone (EEZ): The Coastal State has jurisdiction for the "protection and preservation of the marine environment."
If a discharge causes "substantial" pollution or threatens significant damage, the Coastal State can require information from the vessel.
If the vessel refuses or provides false information, the State may inspect the vessel.
If evidence confirms a violation causing or threatening significant environmental damage, the State may institute legal proceedings (subject to specific transfer-to-flag-state rules if the flag state also acts).
3. Reporting and Cooperation
Notification: The Coastal State must notify the Flag State and the IMO of any measures or proceedings taken regarding violations.
Information Sharing: The State is expected to cooperate with other affected States and the Flag State in the investigation of the casualty, particularly for those classified as "Very Serious."
International Coordination Notification: If the oil slick is projected to cross into the Exclusive Economic Zone (EEZ) or territorial waters of an adjacent nation, the coastal state has a mandatory duty to notify that country immediately, share technical data, and report the event details directly to the IMO.
4. Legal Recourse and Compensation
Liability Regime: The Coastal State enforces the international liability regimes—specifically the CLC (Civil Liability Convention) /Bunker convention and the Fund Convention—to ensure that victims (including the State itself for clean-up costs) receive swift and adequate compensation.
Actionable Recourse: Under the Merchant Shipping Act, 2025, Indian authorities are empowered to pursue shipowners and operators for costs associated with clean-up operations, environmental remediation, and damages caused by the pollution.