Environment and Disaster Management › Protected areas and habitats

Marine 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)

Showing 3 of 7 articles, those that changed from 1 to 30 June 2026.Show all

Coasts under pressure

Great Nicobar project

Prelims 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

The government's own figure for tribal reserve land in the project rose more than tenfold between 2023 and May 2026.Source: Frontline, 8 June 2026

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

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)

Show history (1 other update)

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.
Frontline, 7 Aug 2026: The coastal zone maps that cleared the Great Nicobar port show Galathea Bay as free of corals, while the Zoological Survey of India is planning to translocate the corals that are there. (opens in a new tab)

Coastal adaptation: seawalls, mangroves and managed retreat

Mains

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

Each option carries its own risk, and only the ecosystem route adds livelihood benefits.Source: The Hindu, 5 June 2026

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)

Sand mining at Thottappally

Prelims 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

Removing the sand that holds the sea back turned a harbour works into a loss of farmland.Source: Frontline, 7 June 2026

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)

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.