Lakes of India

Detail

Why lakes matter in a drainage system

• A lake is a large body of still water that sits in a hollow on the land. A river may feed it, drain it, or flow through it.
• The NCERT drainage chapter (Class 11, Ch 3) does not cover lakes. NCERT Class 9 (Contemporary India-I, "Drainage") names Chilika and Pulicat on the east coast. It shows Pangong Tso in a photo and calls it salty because of dissolved minerals.
• What lakes do:
• They control floods. They store extra water in the rains and let it out slowly (for example, Wular on the Jhelum).
• They recharge groundwater. Stored water soaks down into the aquifers below.

• They support fisheries and birds. Chilika supports 118 fish species, and 33 waterbird species breed, winter or stop over there (Ramsar Information Sheet) [3].

• What threatens them:

• Siltation: soil washed in from a bare, deforested catchment makes the lake shallower.
• Encroachment: lake beds are turned into farms, fish ponds or houses.

• Sewage, plus invasive weeds such as water hyacinth.

• Ramsar site: a wetland listed under the Ramsar Convention on Wetlands (1971, Ramsar, Iran) as a "Wetland of International Importance".

• Count: India had 99 Ramsar sites in 26 states and UTs, covering 13,84,181 ha, as on 21 April 2026 [2].
• Most sites: Tamil Nadu (20), then Uttar Pradesh (12) [2].

• The count changes often. Always check the latest figure before the exam.

• Montreux Record: the Ramsar list of sites whose ecological character has changed, is changing or may soon change because of human interference [6].

Classification of lakes by origin

Origin	How it forms (cause → result)	Indian examples
Tectonic	Earth movements (faulting, folding) make a hollow, and water fills it	Wular (partly), J&K; Pangong Tso, Ladakh
Glacial / high-altitude	A glacier scoops out a basin, or its debris (moraine) blocks a valley; melt-water fills it	Tso Moriri (Ladakh), Tsomgo (East Sikkim), Hemkund (Uttarakhand)
Lagoon (coastal)	Waves and currents build a sand bar or spit across a bay; the water behind it is cut off from the open sea	Chilika (Odisha), Pulicat (AP–TN), Vembanad (Kerala)
Fluvial oxbow	A meandering river cuts across the neck of its loop; the old loop is left behind as a curved lake	Kanwar Tal / Kabartal (Begusarai, Bihar)
Crater	A meteorite (or a volcano) blasts a round pit, and rain or groundwater fills it	Lonar (Buldhana, Maharashtra)
Wind-made / inland saline	In a dry region, streams end in a closed hollow; water evaporates and leaves salt behind	Sambhar, Didwana (Rajasthan)
Man-made (reservoirs)	A dam blocks a river and its valley fills up	Gobind Sagar (Bhakra dam, Sutlej, HP); Nagarjuna Sagar (Krishna, Telangana–AP)

• Oxbow lake: a curved lake made when a river leaves one of its loops (meanders). Kanwar Tal (Ramsar name: Kabartal Wetland) in Bihar was designated a Ramsar site on 21 July 2020 and covers 2,620 ha [2].
• Tso Moriri (Ladakh) became a Ramsar site on 19 August 2002 (12,000 ha). Nearby Tso Kar Wetland Complex followed on 17 November 2020 (9,577 ha) [2].
• Man-made lakes can also be Ramsar sites. Examples are Pong Dam Lake (Beas, HP, 2002), Hirakud Reservoir (Mahanadi, Odisha, 2021) and Tawa Reservoir (MP, 2024) [2].

Lonar — India's crater lake

• Location: Buldhana district, Maharashtra, on the Deccan Plateau. The plateau is a huge sheet of volcanic basalt left by eruptions about 65 million years ago [8].
• How it formed:
• A meteorite hit the ground about 35,000–50,000 years ago [8].
• The impact blasted out a round crater about 1,830 m across and about 150 m deep. Its rim rises about 20 m above the land around it [8].

• Rain and groundwater then filled the bottom, making a saline, alkaline lake.

• Proof that it is an impact crater:

• Maskelynite is present. This is a natural glass that forms only in very high-speed impacts [8][9].

• Shocked rock fragments and "shatter cones" are also found [9].

• Why it is special: Lonar is the only known impact crater on Earth formed in basalt. This lets scientists compare it with craters on the Moon and Mars [8][9].

• Ramsar status: designated 22 July 2020, 427 ha [2].

Freshwater and Himalayan lakes

Wular Lake (Jammu and Kashmir)

• Location: in the Kashmir valley, near Bandipora, north of Srinagar. It is one of Asia's largest freshwater lakes. Its Ramsar description calls it India's largest freshwater lake [4].
• Origin: partly tectonic, a sag in the valley floor. The Jhelum river also shapes it.
• Role in floods:
• The Jhelum flows into Wular and leaves it near Sopore.

• In floods the lake soaks up extra water, so it works as a natural flood basin (a low area that stores floodwater).

• Ramsar status: designated 23 March 1990, 18,900 ha [2][4].

• Use:
• Its marshes grow water chestnut, which brings in revenue and gives fodder for animals [4].

• It supports a large fishing industry and supplies water for irrigation and homes [4].

• Problems: the lake is shrinking. Silt comes in from the bare catchment, and willow plantations and farms have spread onto the lake bed.

• Tulbul navigation project: a barrage planned at Wular's outlet to keep the Jhelum navigable in the lean (dry) season. Pakistan has objected to it under the Indus Waters Treaty (1960), so its status keeps changing.

Loktak Lake (Manipur)

• Location: in the Manipur valley, south of Imphal. It is the largest freshwater lake in North-East India.
• Ramsar status: designated 23 March 1990, 26,600 ha [2].
• Phumdis: thick, floating mats of weeds, soil and rotting plant matter that drift on the lake [7].
• Keibul Lamjao National Park:
• It lies on the phumdis in the south of the lake. It is the world's only floating national park.
• It was made a national park in 1977 [7].

• It is the last natural home of the sangai (Manipur brow-antlered deer) [7].

• Ithai barrage:

• It was built on the Ungamel channel, the lake's only outlet, for hydroelectric power and irrigation [7][6].
• It holds the water at a steady high level all year, which upset the natural rise and fall of the lake.

• As a result, phumdis became thinner, the sangai's floating habitat was put at risk, and several native fish species disappeared from the lake [6].

• Montreux Record: Loktak was added in June 1993 [6]. The reasons were:

• deforestation in the catchment
• water hyacinth infestation
• pollution and the effects of the dam [6]

Pangong Tso (Ladakh–Tibet)

• Location and size: in eastern Ladakh, at about 4,350 m. It is about 134 km long, and roughly two-thirds of it lies in Tibet (China).
• Origin: tectonic. It lies in a long, narrow trough between mountain ranges.
• Endorheic means it has no outlet to the sea. Water leaves only by evaporation.

• Because of this, dissolved minerals build up, and the water is brackish (slightly salty; NCERT Class 9: salty because of dissolved minerals).

• Strategic note: its north bank (the "Fingers" area) and south bank (Kailash range) were India–China friction points in 2020–21.

Other high-altitude lakes

• Tsomgo (Changu) Lake: a glacial lake in East Sikkim, on the road to Nathu La.
• Hemkund: a glacial lake in Chamoli district, Uttarakhand. It is a Sikh pilgrimage site.

Coastal lagoons and wetlands

• Lagoon: a shallow body of water near the coast. A sand bar or barrier island separates it from the sea, but it still links to the sea through one or more mouths. River water and sea water mix inside, so the water is brackish (partly salty).

Chilika Lake (Odisha)

• Location: in Puri, Khurda and Ganjam districts, at the south-western edge of the Mahanadi delta. A long sandy ridge separates it from the Bay of Bengal [3].
• Status: it is Asia's largest brackish-water lagoon.
• Salinity: sea water flows in and out, and river water comes in during the monsoon. So the salinity changes sharply by season and from one part of the lake to another [3].
• Ramsar status: designated 1 October 1981, 1,16,500 ha [3][2]. It was one of India's first two Ramsar sites, along with Keoladeo Ghana National Park (Rajasthan) [2].
• Wildlife:
• Irrawaddy dolphins live here, especially near Satapada.

• Nalabana Island is a bird sanctuary that hosts large flocks of winter migratory birds.

• How Chilika was saved:

• Silt from the catchment slowly choked the mouth, so less sea water came in.
• Salinity fell, freshwater weeds spread, and the fish catch dropped. Chilika went onto the Montreux Record in 1993.
• The Chilika Development Authority opened a new mouth in 2000. Sea water came back, the weeds died off, and fish and dolphins recovered.
• Chilika was removed from the Montreux Record in 2002.

Pulicat Lake (Andhra Pradesh–Tamil Nadu)

• Location: on the AP–Tamil Nadu border, north of Chennai. It is India's second-largest brackish lagoon.
• Sriharikota, a barrier island (a long strip of sand parallel to the coast), separates it from the Bay of Bengal. ISRO's launch centre, the Satish Dhawan Space Centre, is on this island.
• Ramsar status: Pulicat is not on India's Ramsar list (as on 21 April 2026) [2]. This is a common exam trap.

Kolleru Lake (Andhra Pradesh)

• Location: a large freshwater lake in the low ground between the Godavari and Krishna deltas. Seasonal streams fill it, and it drains to the sea through the Upputeru channel.
• Ramsar status: designated 19 August 2002, 90,100 ha. It is Andhra Pradesh's only Ramsar site [2].
• How aquaculture damaged it:
• Fish and prawn ponds were dug across the lake bed.
• The open water shrank, and the inflow and outflow channels were blocked.
• Waste from the ponds polluted the water, and bird habitat was lost.

Vembanad Lake (Kerala)

• Location: it stretches from Alappuzha to Kochi. It is India's longest lake and Kerala's largest wetland.
• Rivers: the Periyar, Pamba, Meenachil, Manimala, Achankovil and Muvattupuzha drain into it.
• Kuttanad: the land beside the lake, where rice is grown below sea level.
• Ramsar status: the Vembanad–Kol Wetland was designated 19 August 2002. At 1,51,250 ha it is India's second-largest Ramsar site, after the Sundarban Wetland (4,23,000 ha) [2].
• Nehru Trophy Boat Race: a snake-boat race held on the lake at Alappuzha.

Inland saline lakes

Sambhar Lake (Rajasthan)

• Location: about 80 km west of Jaipur, on the edge of the Thar. It is India's largest inland saline lake.
• Water supply: four main seasonal streams feed it from a catchment of about 2,688 km² [5]. This is centripetal and inland drainage: streams flow inward to a central low point and never reach the sea.
• Size and depth: it is very shallow, only 0.5–2.0 m deep, and covers 24,000 ha [5].
• Why it is salty:
• Monsoon streams carry dissolved salts into a basin with no outlet.
• The strong desert sun evaporates the water.

• The salt stays behind and crusts the lake bed.

• Uses:

• It is a major source of common salt.

• It is a winter home for flamingos.

• Ramsar status: designated 23 March 1990 [2].

• 2019 bird deaths: thousands of migratory birds died in 2019 from avian botulism. This is a paralysing illness caused by a toxin from the bacterium Clostridium botulinum, which grows in warm, stagnant water.
• Didwana (Nagaur district) is a smaller saline lake of the same type.

Ramsar data for the lakes in this section

Lake	State/UT	Date of designation	Area (ha)
Chilika	Odisha	01-10-1981	1,16,500
Wular	J&K	23-03-1990	18,900
Loktak	Manipur	23-03-1990	26,600
Sambhar	Rajasthan	23-03-1990	24,000
Kolleru	Andhra Pradesh	19-08-2002	90,100
Vembanad–Kol	Kerala	19-08-2002	1,51,250
Tso Moriri	Ladakh	19-08-2002	12,000
Kabartal (Kanwar Tal)	Bihar	21-07-2020	2,620
Lonar	Maharashtra	22-07-2020	427

Source: MoEFCC list, as on 21 April 2026 [2].

Prelims Hooks

• India's first two Ramsar sites (1981): Chilika (Odisha) and Keoladeo Ghana NP (Rajasthan) [2].
• Wular, Loktak and Sambhar were all designated on the same day: 23 March 1990 [2].
• Pulicat is NOT a Ramsar site (as on April 2026), even though it is India's second-largest brackish lagoon [2].
• Largest Ramsar sites: Sundarban (4,23,000 ha) is the largest. Vembanad–Kol (1,51,250 ha) is second, ahead of Chilika (1,16,500 ha) [2].
• Lonar is the only known terrestrial impact crater in basalt (Buldhana, Maharashtra; Ramsar 2020) [8][2].
• Keibul Lamjao (on Loktak) is the only floating national park, home of the sangai deer. It was made an NP in 1977 [7].
• Montreux Record: Loktak was added in 1993 [6]. Chilika was removed in 2002 after a new mouth was opened.
• Lake–type pairs: Kanwar Tal = oxbow; Lonar = crater; Pangong Tso = tectonic and endorheic; Chilika/Pulicat/Vembanad = lagoon; Gobind Sagar = reservoir on the Sutlej (Bhakra).
• Barrier island trap: Sriharikota separates Pulicat from the sea. It is not linked to Chilika.
• State with the most Ramsar sites: Tamil Nadu (20), as on April 2026 [2].

Mains Points

• Lakes are part of the drainage system.
• Wular stores Jhelum floodwater. Sambhar is the end point of inland centripetal drainage. Lagoons like Chilika are where river water meets sea water.

• When these lakes are lost, flood peaks rise and groundwater falls (GS-I, GS-III disasters).

• How lakes decline:

• deforestation in the catchment → siltation → the lake becomes shallower and its mouth chokes
• encroachment for aquaculture (Kolleru) or plantations (Wular), along with sewage and invasive weeds

• result: smaller lakes, lost fisheries and lost biodiversity [6][4].

• Dams change lake ecology.

• The Ithai barrage keeps Loktak's water level fixed. This thinned the phumdis, threatened the sangai and wiped out native fish [6].

• This shows a trade-off between hydropower and irrigation on one side and wetland health on the other (GS-III).

• Restoration works when it fixes how water flows.

• Chilika: opening a new mouth in 2000 → sea water returned → removed from the Montreux Record in 2002.
• The model is an authority for each lake (Chilika and Loktak Development Authorities) plus Ramsar listing, which grew to 99 sites by April 2026 [2]. It can be used for other stressed lakes.