Environment and Disaster Management › Protected areas and habitats
हिन्दी — Read in HindiMarine and coastal ecosystems
Coasts and seas as ecosystems: mangroves, seagrass, estuaries and lagoons, coastal regulation and erosion, marine protected areas and the treaties for the high seas. Prelims has asked what blue carbon is and where India has coral reefs.
Foundation note: Coral reefs of India
UPSC has asked
- Prelims 2026: why mangroves matter for climate resilience
- Prelims 2016: The Economics of Ecosystems and Biodiversity (TEEB)
Fisheries and the deep sea
National report on deep-sea fishery resources
Copy link to National report on deep-sea fishery resourcesPrelims and Mains
The national report on deep sea fishery resources is the Ministry of Earth Sciences' account of the fish in India's deep water, below the reach of light.
- The mesopelagic zone, 200 to 1,000 metres down, holds lanternfishes, deep sea shrimps and squids, most of the ocean's fish by weight.
- The banks and slopes that hold them are the ones a fleet could strip.
- India's research vessel Sagar Sampada has surveyed its deep water for three decades.
What changed
20 Aug 2026BriefThe Ministry of Earth Sciences released a national report on deep sea fishery resources, drawing on the cruises of Sagar Sampada. It flags Kollam Bank, Angria Bank, the Mangalore slope, the Thiruvananthapuram terrace, Lakshadweep and the Andaman and Nicobar Islands as vulnerable areas. PIB, 20 Aug 2026: National report on deep-sea fishery resources and marine hotspots (opens in a new tab)
Marine fish stock accounts
Copy link to Marine fish stock accountsPrelims and Mains
Marine fish stock accounts apply natural capital accounting, which records natural assets and their depletion, to India's marine fish stocks.
- Gross domestic product (GDP) misses depletion: a fishery counts in GDP as the fish landed, not as the stock left behind.
- The United Nations System of Environmental Economic Accounting is the framework, and the Ministry of Statistics and Programme Implementation (MoSPI) is testing it, so that what a fleet takes can be set against what the taking costs.
Judge the stock
Compare current landings with ten years of landing data
Resource rent
Income left after labour, costs, depreciation and a normal return on vessels
Discount
Future rents brought to present value at a 2% real rate
Asset account
Shows whether the stock is maintained, depleted or regenerating
What changed
31 Aug 2026BriefMoSPI set out how it would build natural capital and climate risk accounts for the blue economy, starting with marine fish stocks; the method is in the figure. The Hindu, 31 Aug 2026: India's plan to begin natural-capital and climate-risk accounting of its blue economy | Explained (opens in a new tab)
Coasts under pressure
Great Nicobar project
Copy link to Great Nicobar projectPrelims and Mains
The Great Nicobar project is a plan for an International Container Transshipment Port at Galathea Bay, a greenfield joint use airport, a township and a power plant on Great Nicobar Island.
- It covers 166.1 sq km of the 921 sq km island.
Two figures for the tribal reserve
| Government statement | Tribal reserve land in the project |
|---|---|
| 2023 | 7.11 sq km |
| 1 May 2026 | 84.1 sq km |
Why the island matters
- The island is a biodiversity hotspot and home to the Shompen, a particularly vulnerable tribal group.
- The giant leatherback turtle nests at Galathea Bay, whose wildlife sanctuary was denotified in 2021 to make way for the port.
- The island is seismically active and subsided in the 2004 earthquake.
- Island coasts are zoned under the Island Coastal Regulation Zone framework, in which category IA is the most restrictive.
What changed
7 Aug 2026newly added
- The Zoological Survey of India records a reef of 116 hectares with more than 100 species of reef building coral in Galathea Bay, while the 2023 coastal maps of the National Centre for Sustainable Coastal Management show no coral there.
- A site with coral reef falls in the most protected coastal category, where a port cannot be built.
- The submission that the bay is a lower category was central to the National Green Tribunal dismissing objections in February 2026.
Mains: a mapping decision, and not an environmental argument, settled what the project may legally do.
12 Jun 2026
- The Zoological Survey of India chose four west coast sites to move coral and giant clam colonies from the port area, both Schedule I species.
- A Wildlife Institute of India survey found leatherback nests at Galathea Bay.
- The government now says 84.1 sq km of the project falls in tribal reserves, against its 2023 figure of 7.11 sq km.
The Indian Express, 12 Jun 2026: 4 sites on Nicobar west coast identified for coral translocation, says Zoological Survey of India (opens in a new tab) · Frontline, 8 Jun 2026: Great Nicobar's blueprint for 'development at any cost' (opens in a new tab)
Coastal adaptation: seawalls, mangroves and managed retreat
Copy link to Coastal adaptation: seawalls, mangroves and managed retreatMains
Coastal protection has three options: hold the line with seawalls and groynes, retreat, or use ecosystems as the buffer.
- Hard armouring can shift erosion to the next stretch of coast, as on Kerala's coast, and can draw investment into hazard zones, which is maladaptation.
- Managed retreat is one of the four coastal adaptation strategies of the Intergovernmental Panel on Climate Change (IPCC).
- Ecosystem based adaptation uses mangroves, seagrass, reefs and wetlands as buffers with livelihood benefits.
- India undercounts it because it sits inside restoration schemes such as the Mangrove Initiative for Shoreline Habitats and Tangible Incomes (MISHTI) under other labels.
Three ways to meet the sea
| Hold the line | Managed retreat | Ecosystem based | |
|---|---|---|---|
| What it is | Seawalls and groynes that fix the shoreline | Moving people and assets away from the hazard | Mangroves, seagrass, reefs and wetlands as buffers |
| Indian example | Kerala's armoured coast | Satabhaya to Bagapatia, Odisha, 2018 | The Sundarbans and Bhitarkanika |
| Risk | Shifts erosion to the next stretch | Livelihood loss | Undercounted, so rarely planned for |
What changed
5 Jun 2026New
- The National Coastal Mission's budget fell between 2022 to 2023 and 2024 to 2025, while coastal States kept spending on hard protection.
- In the Sundarbans women restored mangroves that blunted cyclones Amphan and Yaas.
- Bhitarkanika's mangroves held the coast when Cyclone Dana landed.
- Odisha's 2018 relocation of families from Satabhaya to Bagapatia is the Indian example of retreat, where landowners became daily wage labourers.
- The Kosi embankments of the 1954 India Nepal agreement confine the river so silt raises its bed above the land, making breaches catastrophic.
Mains: India must classify and measure ecosystem based adaptation and plan receiver towns for coastal retreat, rather than claim a right to engineer its way out of adaptation.
The Hindu, 5 Jun 2026: When mangroves do what seawalls cannot (opens in a new tab) · The Hindu, 5 Jun 2026: Caught between concrete and panic, India should not maladapt to climate change (opens in a new tab)
See also: MISHTI
Sand mining at Thottappally
Copy link to Sand mining at ThottappallyPrelims and Mains
The Kollam to Alappuzha coast is dense black sand rich in ilmenite, monazite, rutile, zircon and sillimanite.
- The sand acts as a natural wall against erosion and keeps sea water out of the backwaters.
- The Thottappally spillway of 1954 and its estuary drain low lying Kuttanad, about 3 m below sea level, to the sea, and the estuary's fine grains stabilise the coast.
- Monazite in the sand is radioactive, so stockpiles in the open are a radiation source.
From dredging to lost paddy
Harbour dredging
Dredging for the harbour, 2010 to 2014
Estuary mining
Mining of the estuary sand expands after the 2018 flood
Barrier lost
The black sand wall between sea and backwater thins
Erosion and salt
The coast erodes and salt water intrudes
Paddy lost
About 3,000 hectares of Kuttanad paddy land became uncultivable between 2020 and 2023
What changed
7 Jun 2026New
- Estuary sand mining by Indian Rare Earths Limited and Kerala Minerals and Metals Limited, expanded after the 2018 flood, is eroding the coast.
- About 3,000 hectares of Kuttanad became uncultivable between 2020 and 2023 from salt water intrusion.
- A December 2025 Kerala High Court case on harm to paddy and nesting sea turtles led to an expert committee.
Mains: Dredging justified as harbour maintenance and disaster management has become mineral extraction that worsens erosion, salinity and radiation exposure; the government cites IIT Madras and Swaminathan Commission studies in its defence.
Frontline, 7 Jun 2026: Black sand, broken shores (opens in a new tab)
Mangroves
Mangrove roots slow waves and trap sediment, which is why a mangrove belt is counted as coastal defence rather than only as forest. India is doing two things to its mangroves at once: planting them back under a national programme, and learning to price the ones still standing, since a forest that carries no price loses every planning decision it enters.
MISHTI
Copy link to MISHTIPrelims and Mains
MISHTI, the Mangrove Initiative for Shoreline Habitats and Tangible Incomes, was launched on World Environment Day 2023 to restore about 540 sq km of mangroves along the coast.
- It is funded through the National CAMPA fund, with States planting and communities earning from the restored belts.
- Mangroves grow where the tide meets fresh water; a few, as at Guneri in Kachchh, Gujarat's first Biodiversity Heritage Site, grow inland away from the sea.
What changed
10 Jul 2026BriefThe governing body of the National Compensatory Afforestation Fund Management and Planning Authority (CAMPA) extended MISHTI by three years to 2029 and raised its outlay to ₹600 crore. It moved the scheme to a landscape based approach to coastal restoration. PIB, 10 Jul 2026: Four new Wildlife and Forestry Conservation Projects for Dolphins, Snow Leopards, Wild Water Buffalo and Indian Rhinoceros approved by GB CAMPA (opens in a new tab)
India's mangroves: what they are worth and what they lose
Copy link to India's mangroves: what they are worth and what they losePrelims and Mains
Blue carbon is the carbon stored by coastal ecosystems such as mangroves, salt marshes and seagrass, in the standing wood and in the waterlogged sediment below.
Sediments76%
Vegetation24%
What a mangrove holds
- A lack of oxygen keeps the sediment's carbon from rotting, so mangrove soil holds its carbon only as long as it stays wet and undug.
- Total Economic Value is an ecosystem's use values plus its non use values, such as coastal protection and the worth of keeping it in existence.
- A forest enters a planning decision only once someone has worked that value out.
Where India's mangroves are
- Pichavaram in Tamil Nadu, between the Vellar and Coleroon estuaries, is one of India's largest mangrove forests.
- West Bengal holds the largest share of India's mangrove cover, 42.45 per cent, almost all of it in the Sundarbans.
- There the forest is being converted to fish ponds known locally as bheries.
What changed
25 Jul 2026
- A survey of ten locations found more than 600 hectares of Sundarbans mangrove converted into bheries, cleared from inside so that the forest still looks dense from the water.
The Hindu, 25 Jul 2026: Will restore mangroves lost to encroachments: Minister (opens in a new tab)
UPSC has asked
- Prelims 2021: what blue carbon is
Also filed elsewhere
- India's deep sea mining programme · on Ocean, polar and earth science missions
India's deep sea mining programme explores the seabed for minerals under three International Seabed Authority contracts.