Oil pollution fouls the ocean with petroleum that kills marine life and smothers coasts.
India’s long coastline and busy shipping lanes make it especially exposed to this threat.
Must Know
Oil Pollution: What It Is
What oil pollution is
- DefinitionOil pollution is the release of petroleum hydrocarbons into the sea or coastal environment.
- FormsIt includes crude oil, refined fuels, bunker oil and oily ship waste.
- ResultThe oil forms slicks, sheens and tar that foul water and shores.
- ExtentEven small, repeated discharges poison waters far from any single spill.
The main sources of oil pollution
- TankersTanker accidents release huge volumes of crude oil at sea.
- ShippingShips discharge oily ballast and bilge water, legally and illegally.
- OffshoreBlowouts and pipeline leaks add oil from offshore platforms.
- LandRivers and coastal industries carry oil from the land to the sea.
- NaturalNatural seabed seeps release small amounts of oil on their own.
How oil behaves in the sea
- SpreadingWind and currents spread oil into a thin surface slick.
- EvaporationLighter fractions evaporate into the air within days.
- EmulsifyingOil and water mix into a thick, sticky emulsion called mousse.
- WeatheringSun, waves and bacteria slowly break the remaining oil down.
Key terms to remember
- SlickA slick is a thin layer of oil floating on the sea surface.
- MousseMousse is a stable water-in-oil emulsion that resists breakdown.
- SheenA sheen is a faint, rainbow-coloured film of oil on water.
- TarballA tarball is a hardened lump of weathered oil that drifts at sea.
Good to Know
Impacts on the Marine Ecosystem
Impacts on marine wildlife
- BirdsOil coats feathers and destroys their waterproofing and insulation.
- DrowningOiled birds lose buoyancy, chill quickly and often drown.
- MammalsMarine mammals inhale fumes or swallow oil while grooming.
- FishOil damages the gills, eggs and larvae of fish and shellfish.
- PlanktonOil blocks light and poisons plankton, the base of the food web.
Impacts on coastal habitats
- MangrovesOil clogs mangrove roots and can kill whole coastal forests.
- CoralsOil and dispersants smother corals and can trigger bleaching.
- SeagrassSmothered seagrass beds lose their role as fish nurseries.
- BeachesTarballs and buried oil linger on beaches for years.
- EstuariesEstuaries trap oil and pass its toxins into nursery grounds.
Impacts on food webs and people
- BioaccumulationOil toxins build up as they move up the food chain.
- FisheriesContaminated fish and closed grounds destroy fishing incomes.
- TourismOil-fouled beaches repel tourists and hurt coastal towns.
- EconomyMajor spills cost billions in cleanup and lost livelihoods.
Test Yourself
Great to Know
India: Vulnerability and Response
Why India is especially vulnerable
- CoastlineIndia’s mainland coastline stretches for about 7,500 kilometres.
- WatersIt faces the Arabian Sea, the Bay of Bengal and island seas.
- RoutesDense tanker routes run along both of India’s coasts.
- PortsKandla, Mumbai, Chennai and Paradip handle heavy oil traffic.
- HabitatsCoral reefs, mangroves and estuaries line the Indian coast.
- PeopleMillions of Indians depend on fishing and coastal livelihoods.
Major oil spills, including near India
- Exxon ValdezThe Exxon Valdez spilled crude oil off Alaska in 1989.
- Deepwater HorizonA 2010 blowout spilled oil in the Gulf of Mexico for months.
- Mumbai 2010The MSC Chitra collision off Mumbai spilled fuel oil in August 2010.
- Chennai 2017A tanker collision off Ennore fouled Chennai’s beaches in January 2017.
India’s institutional response
- Coast GuardThe Indian Coast Guard leads oil spill response in Indian waters.
- PlanThe National Oil Spill Disaster Contingency Plan, framed in 1996, guides response.
- LawThe Merchant Shipping Act and its amendments penalise oily discharge.
- ConventionsIndia is a party to MARPOL and the OPRC Convention.
- OPRCThe OPRC Convention requires national preparedness plans for oil spills.
Prevention, response and clean-up
- PreventionDouble-hull tankers sharply reduce the risk of major spills.
- ContainmentBooms and skimmers contain and collect oil at the surface.
- DispersantsDispersants break slicks into droplets for faster natural decay.
- BioremediationOil-eating microbes help clean residual oil from shorelines.
- WastePort reception facilities let ships offload oily waste legally.
PYQ
Previous Year Questions
2023 Mains — GS Paper III
- Mains 2023UPSC CSM 2023 GS Paper III, Q8 — View this question
- AskThe question joins definition, ecological impact and the India angle.
- PlanDefine oil pollution, list marine impacts, then give India-specific vulnerability.
- TipName NOSDCP, the Coast Guard and MARPOL for a complete answer.
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