BPSC 71st CCE Prelims General Studies · Question 113 of 150

Correct — B, Lake. 'Loktak' is Loktak Lake in Manipur, the largest freshwater lake in North-East India, lying at an elevation of about 768.5 m with Imphal and Moirang on or near its shores. It is described as a 'pulsating' lake because its surface swings between roughly 250 sq km and 500 sq km with the seasons around a typical 287 sq km; it runs about 35 km long by 13 km wide, is only 2.7 m deep on average and 4.6 m at its deepest, and collects a catchment of 980 sq km fed by the Manipur river and a mass of smaller rivulets. The name settles the category by itself: in Meitei, 'lok' means stream and 'tak' means the end — the place where the streams end. India designated it a Ramsar Wetland of International Importance on 23 March 1990 as site number 463, and it was placed on the Montreux Record on 16 June 1993, the Ramsar register of listed sites whose ecological character has changed or is likely to change. Its signature feature is the phumdi — a floating, heterogeneous mat of vegetation, soil and organic matter solid enough to walk on and to build fishing huts upon. Keibul Lamjao National Park rests on a phumdi of about 40 sq km and is the only floating national park on earth; it is the last natural refuge of the sangai or brow-antlered deer, Rucervus eldii eldii, Manipur's state animal, which survives in the wild nowhere else. The lake is not a curiosity but the working heart of the State's economy: it supplies water for hydropower generation, irrigation and drinking supply, and it is the livelihood of the rural fishing communities who live on and around the phumdis.

• (a)Valley — The sharpest trap, because Manipur's central lowland genuinely is called the Imphal Valley and Loktak is its remnant. That valley is a lacustrine plain of about 1,864 sq km at an average 790 m, formed by the silting-up of an ancient lake — Loktak is what survives of the lake. 'Valley' names the basin, not the water standing in it.
• (c)River — Manipur's rivers are the Manipur (Imphal), the Iril, the Thoubal and the Barak, and Loktak's own inflow is the Manipur river system — so the word sits in genuinely riverine company. But Loktak is the standing water that system feeds, not a channel; its outflow today passes through a barrage built for hydropower, irrigation and water supply.
• (d)Mountain series — Manipur has real and examinable hill ranges — the Barail, the Naga Hills to the north, the Manipur hills flanking the valley — and 'Loktak' carries the sound of a Tibeto-Burman toponym, which is why the option is offered. No range bears the name. UPSC ran the reverse trick in 2013 by pairing 'Loktak Lake : Barail Range' and marking it wrong.

The Ramsar Convention on Wetlands, signed at Ramsar in Iran in 1971, commits its parties to the wise use of wetlands; a site enters the List of Wetlands of International Importance on the country's own nomination against ecological, botanical, zoological, limnological or hydrological criteria. As of the 13 September 2025 exam India had 91 Ramsar sites, three of them in Bihar — Kabartal Wetland in Begusarai (21 July 2020) and Nagi and Nakti Bird Sanctuaries in Jamui (both 11 October 2023). Three more Bihar wetlands were listed later the same month, Udaypur Lake and Gokul Reservoir on 25 September and Gogabeel on 27 September, so present-day totals do not answer a question dated to the exam. The Montreux Record is a separate and unwelcome register kept inside the same framework: it flags already-listed sites where ecological character has changed, is changing, or is likely to change through human interference. Loktak's 1993 entry on it is the whole story of the lake. The Ithai barrage of the Loktak hydroelectric project holds the water at an artificially steady level, and phumdis need to ground on the lake bed in the dry season to draw nutrients from it; kept permanently afloat they thin, and as they thin the sangai loses the only ground it can stand on.

Elimination does most of the work here, and each elimination is worth knowing on its own rather than guessing. 'Valley' is the right answer to a different question — the Imphal Valley, a lacustrine plain of about 1,864 sq km, is the basin, and Loktak is the residual water body at its lowest point. 'River' belongs to the Manipur, Iril, Thoubal and Barak. 'Mountain series' belongs to the Barail and the Naga hills. That leaves 'lake', and every associated fact confirms it, because you cannot have a Ramsar wetland, a floating national park, a phumdi or a hydroelectric barrage on a mountain range. If you want one line to carry into the hall, make it Keibul Lamjao: the world's only floating national park floats on Loktak, and a national park cannot float on a valley or a river. The reason BPSC could set this as a bare fill-in-the-blank rather than a matching item is that the word does almost no work by itself for a candidate who has never met it — it is pure recall, and the recall chain worth building is Loktak → phumdi → sangai → Keibul Lamjao, because every one of those four words has been examined separately.

• Loktak Lake, Manipur, is the largest freshwater lake in North-East India — about 35 km by 13 km, average depth 2.7 m, maximum 4.6 m, at an elevation of 768.5 m with a catchment of 980 sq km.
• It is a 'pulsating' lake whose surface area varies from about 250 sq km to 500 sq km with the seasons, around a typical 287 sq km; its inflow is the Manipur river and many rivulets, and its outflow now passes through a barrage built for hydropower, irrigation and water supply.
• Ramsar site number 463, designated 23 March 1990; placed on the Montreux Record on 16 June 1993 — the Ramsar register of already-listed sites whose ecological character has changed, is changing or is likely to change through human interference.
• Keibul Lamjao National Park sits on a phumdi of roughly 40 sq km and is the world's only floating national park; it is the last natural refuge of the sangai (Rucervus eldii eldii), Manipur's state animal, which survives in the wild nowhere else.
• In Meitei 'lok' means stream and 'tak' means the end; Loktak Day is observed on 15 October, the lake's islands include Thanga, Ithing and Sendra, and Imphal and Moirang stand on or near its shores.

• Choosing 'valley' because the Imphal Valley is real — the valley is the basin, Loktak is the lake inside it
• Confusing the Ramsar designation date (23 March 1990) with the Montreux Record date (16 June 1993)
• Assuming Keibul Lamjao is a floating island rather than a national park sitting on one, or calling Loktak itself the national park

BPSC asks it as a naked fill-in-the-blank — is Loktak a valley, lake, river or range — one recall mark with no reasoning path. UPSC has never asked the category directly; it asked in 2013 whether 'Loktak Lake : Barail Range' was correctly matched and in 2015 which national park is a swamp with floating vegetation, so UPSC tests the ecology and the location while BPSC tests only the noun.

• practice — not a real PYQ

  Keibul Lamjao National Park, the only floating national park in the world, is located in which State ?

  • (a)Assam
  • (b)Meghalaya
  • (c)Manipur
  • (d)Tripura

  Answer(c) Manipur — it floats on a phumdi of about 40 sq km on Loktak Lake and is the last natural home of the sangai, Manipur's state animal.

• practice — not a real PYQ

  The 'phumdis' associated with Loktak Lake are

  • (a)Terraced paddy fields on the valley slopes
  • (b)Floating masses of vegetation, soil and organic matter
  • (c)Traditional fishing traps woven from bamboo
  • (d)Seasonal sandbars deposited by the Manipur river

  Answer(b) Floating masses of vegetation, soil and organic matter — thick enough to carry huts and to support Keibul Lamjao National Park; they thin when the Ithai barrage prevents them grounding in the dry season.