India: relief, rivers, lakes and monsoon: previous-year questions
40 real UPSC Prelims questions (2011–2026) with the official answer and a clear explanation. 12 of them came in the last five papers.
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Questions per year, counted from the official papers.
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Which one of the following is an artificial lake ?
Answer (a) & explanation
Kodaikanal Lake is artificial (a). This star-shaped lake in the Palani Hills, Tamil Nadu, was created in 1863 by Sir Vere Henry Levinge, then Collector of Madurai, by damming streams. Kolleru (b) is a large natural freshwater lake between the Godavari and Krishna deltas in Andhra Pradesh, a Ramsar site and bird sanctuary. Nainital (c) is a natural lake in Kumaon, generally thought to be tectonic in origin. Renuka (d) in Sirmaur, Himachal, is a natural lake, the largest in the state, and a Ramsar site.
Notice other well-known man-made lakes: Hussain Sagar (Hyderabad), Sukhna (Chandigarh), Govind Ballabh Pant Sagar (Rihand, UP), and Ooty Lake. India now has over 90 Ramsar sites.
Answer as per the official UPSC answer key.
Consider the following statements :
- 1. The Barren Island volcano is an active volcano located in the Indian territory.
- 2. Barren Island lies about 140 km east of Great Nicobar.
- 3. The last time the Barren Island volcano erupted was in 1991 and it has remained inactive since then.
Which of the statements given above is/are correct ?
Answer (a) & explanation
Only statement 1 is correct (a). Barren Island, in the Andaman Sea, is India's only confirmed active volcano, and the only one in South Asia. Statement 2 is wrong because it lies about 140 km north-east of Port Blair, not east of Great Nicobar. Statement 3 is wrong because, after waking in 1991 following about 200 years of rest, it erupted again in 1994–95, 2005–07, 2017 and later. It sits where the Indian Plate slides under the Burma microplate.
Do not confuse it with Narcondam, a dormant volcano to its north and home of the Narcondam hornbill. Notice the link to the 2004 tsunami, caused by the same subduction zone off Sumatra.
Answer as per the official UPSC answer key.
At one of the places in India, if you stand on the seashore and watch the sea, you will find that the sea water recedes from the shore line a few kilometres and comes back to the shore, twice a day, and you can actually walk on the sea floor when the water recedes. This unique phenomenon is seen at
Answer (c) & explanation
This happens at Chandipur (c). At Chandipur beach in Balasore district, Odisha, the shore slopes so gently that at low tide the sea pulls back up to about 5 km. You can walk on the exposed sea floor, and the water returns with the next tide, twice a day. This "hide-and-seek beach" is also home to horseshoe crabs, and DRDO's Integrated Test Range for missiles is nearby. Bhavnagar (a) is in Gujarat and has high tides but no such walkable retreat. Bheemunipatnam (b) and Nagapattinam (d) are ordinary beaches.
Tides happen twice a day because of the Moon's pull. Notice the extremes: the Gulf of Khambhat has India's highest tidal range, which makes it a site for possible tidal power.
Answer as per the official UPSC answer key.
With reference to river Teesta, consider the following statements :
- 1. The source of river Teesta is the same as that of Brahmaputra but it flows through Sikkim.
- 2. River Rangeet originates in Sikkim and it is a tributary of river Teesta.
- 3. River Teesta flows into Bay of Bengal on the border of India and Bangladesh.
Which of the statements given above is/are correct ?
Answer (b) & explanation
Only statement 2 is correct (b). Statement 1 is wrong because the Teesta rises from glaciers and lakes in north Sikkim, such as Tso Lhamo/Cholamu and the Zemu glacier near Kangchenjunga. The Brahmaputra starts at the Chemayungdung glacier near Mansarovar in Tibet. Statement 2 is right because the Rangeet rises in west Sikkim and joins the Teesta near the Sikkim–West Bengal border. Statement 3 is wrong because the Teesta flows into the Brahmaputra (Jamuna) inside Bangladesh, not straight into the Bay of Bengal.
The Teesta water-sharing deal with Bangladesh is still unsigned because of West Bengal's objections. Notice the related events: the South Lhonak GLOF in October 2023 destroyed the Chungthang dam, and China has offered to fund Teesta projects in Bangladesh.
Answer as per the official UPSC answer key.
If you travel by road from Kohima to Kottayam, what is the minimum number of States within India through which you can travel, including the origin and the destination ?
Answer (b) & explanation
The minimum is seven States (b). The shortest route by number of States is Nagaland → Assam → West Bengal → Odisha → Andhra Pradesh → Tamil Nadu → Kerala, which is seven States, including the start and end. The narrow Siliguri Corridor ("Chicken's Neck") makes passing through West Bengal unavoidable. Going inland through Bihar, Jharkhand, Chhattisgarh or Telangana adds States, so 8 (c) or 9 (d) is not the minimum, and 6 (a) is not possible.
The national highway along the east coast makes this route practical. Notice the strategic point: the Siliguri Corridor, about 20–22 km wide, is the northeast's only land link to the rest of India, which is why projects through Bangladesh and the Kaladan route matter.
Answer as per the official UPSC answer key.
Consider the following statements :
- 1. In India, the Himalayas are spread over five States only.
- 2. Western Ghats are spread over five States only.
- 3. Pulicat Lake is spread over two States only.
Which of the statements given above is/are correct ?
Answer (b) & explanation
Only statement 3 is correct (b). Statement 1 is wrong because the Indian Himalayas cross many States and UTs, about 12: Jammu & Kashmir, Ladakh, Himachal Pradesh, Uttarakhand, Sikkim, West Bengal (Darjeeling), Arunachal Pradesh, and the northeastern hill ranges. Statement 2 is wrong because the Western Ghats run through six States: Gujarat, Maharashtra, Goa, Karnataka, Kerala and Tamil Nadu. Statement 3 is right because Pulicat Lake, India's second-largest brackish lagoon, lies in Andhra Pradesh and Tamil Nadu only.
Sriharikota, with ISRO's launch centre, separates Pulicat from the sea. Notice that Chilika (Odisha) is the largest lagoon. The Western Ghats are a UNESCO site (2012) and one of the world's biodiversity hotspots.
Answer as per the official UPSC answer key.
With reference to ‘Indian Ocean Dipole (IOD)’ sometimes mentioned in the news while forecasting Indian monsoon, which of the following statements is/are correct ?
- 1. IOD phenomenon is characterised by a difference in sea surface temperature between tropical Western Indian Ocean and tropical Eastern Pacific Ocean.
- 2. An IOD phenomenon can influence an El Nino’s impact on the monsoon.
Select the correct answer using the code given below :
Answer (b) & explanation
Only statement 2 is correct (b). Statement 1 is wrong because the Indian Ocean Dipole is the difference in sea-surface temperature between the western Indian Ocean (Arabian Sea, off Africa) and the eastern Indian Ocean (near Sumatra–Java), not the Pacific. In a positive IOD, the western waters are warmer, which brings more rain to India. Statement 2 is right because a positive IOD can offset El Niño's drying effect. In 1997, a strong El Niño year, the monsoon was still normal.
A positive IOD also fuelled the strong 2019 monsoon and the Australian bushfires. Notice the related term ENSO: El Niño (a warm Pacific) usually weakens the monsoon, while La Niña strengthens it. The IMD watches both when forecasting.
Answer as per the official UPSC answer key.
Which of the following is/are tributary/tributaries of Brahmaputra?
- 1. Dibang
- 2. Kameng
- 3. Lohit
Select the correct answer using the code given below.
Answer (d) & explanation
All three are tributaries (d). In Arunachal Pradesh, the Siang meets the Dibang (1) and the Lohit (3) near Sadiya, and from there the river is called the Brahmaputra. The Kameng (2), known as the Jia Bharali in Assam, rises near the Tawang area and joins the Brahmaputra from the north near Tezpur. Any option leaving out one of them is incomplete.
Other right-bank (northern) tributaries are the Subansiri, Manas and Sankosh; left-bank ones include the Burhi Dihing, Dhansiri and Kopili. Notice how the Tsangpo in Tibet becomes the Siang, then the Brahmaputra, and finally the Jamuna in Bangladesh.
Answer as per the official UPSC answer key.
Recently, linking of which of the following rivers was undertaken?
Answer (b) & explanation
The Godavari and Krishna were linked (b). In September 2015, Andhra Pradesh completed the Pattiseema lift irrigation scheme. It pumps surplus Godavari water into the Polavaram right main canal, which carries it about 174 km to the Krishna near Vijayawada (Prakasam barrage). It was the first river link actually finished in India. Cauvery–Tungabhadra (a), Mahanadi–Sone (c) and Narmada–Tapti (d) were not done then. The Par–Tapi–Narmada link has since been shelved.
Under the National Perspective Plan (1980), the Ken–Betwa link (MP–UP) is the first project under the national programme, and its foundation stone was laid in December 2024. Notice the debate around such links: they threaten forests like Panna Tiger Reserve.
Answer as per the official UPSC answer key.
In a particular region in India, the local people train the roots of living trees into robust bridges across the streams. As the time passes, these bridges become stronger. These unique ‘living root bridges’ are found in
Answer (a) & explanation
Living root bridges are found in Meghalaya (a). The Khasi and Jaintia people guide the aerial roots of the rubber fig (Ficus elastica) across streams, and over years the roots grow into strong bridges, such as the famous double-decker bridge at Nongriat. Himachal Pradesh (b), Jharkhand (c) and Tamil Nadu (d) do not have this tradition.
The bridges grow stronger with age and can last for centuries. The "Jingkieng Jri" root bridge landscapes were placed on UNESCO's tentative list in 2022. Notice how this shows indigenous engineering working with nature: a model of sustainable infrastructure.
Answer as per the official UPSC answer key.
Which one of the following pairs of States of India indicates the easternmost and westernmost State?
Answer (d) & explanation
India's eastern limit, about 97°25′ E, lies in Arunachal Pradesh in the Dibang–Lohit area near Kibithu. The western limit, about 68°7′ E, lies in Gujarat at Guhar Moti in Kutch. So the answer is (d). Assam (a, c) lies west of Arunachal, and Rajasthan's western border (a, b) lies east of Kutch.
The roughly 30° spread of longitude creates about a two-hour difference in local time between the two ends. That is why India uses one standard meridian, 82°30′ E through Mirzapur, and why the North-East has long asked for its own time zone. Notice how geography shapes daily life.
Answer as per the official UPSC answer key.
Consider the following pairs :
| Place of Pilgrimage | Location
| 1. Srisailam | Nallamala Hills
| 2. Omkareshwar | Satmala Hills
| 3. Pushkar | Mahadeo Hills
Which of the above pairs is/are correctly matched?
Answer (a) & explanation
Only pair 1 is correct (a). The Srisailam jyotirlinga stands in the Nallamala Hills of the Eastern Ghats, beside the Krishna, in Andhra Pradesh. Omkareshwar is on an island in the Narmada, between the Vindhya and Satpura ranges in Madhya Pradesh, not in the Satmala Hills, which are in Maharashtra. Pushkar, with its lake and Brahma temple, lies in the Aravalli hills near Ajmer, not in the Mahadeo Hills (Pachmarhi).
The Nallamala forests also hold the Nagarjunasagar–Srisailam Tiger Reserve, India's largest. Notice how pilgrimage sites follow rivers and hills, linking culture with physical geography.
Answer as per the official UPSC answer key.
Consider the following rivers :
- 1. Vamsadhara
- 2. Indravati
- 3. Pranahita
- 4. Pennar
Which of the above are tributaries of Godavari?
Answer (d) & explanation
The Indravati, rising in Odisha and flowing through Bastar, and the Pranahita, formed by the Wardha and Wainganga, are left-bank tributaries of the Godavari (d). The Vamsadhara and the Pennar are separate east-flowing rivers that reach the Bay of Bengal on their own, so options with 1 or 4 fail.
The Godavari is the largest river of peninsular India, often called the Dakshin Ganga. Other tributaries include the Manjira and the Sabari. The Vamsadhara has been the subject of an Andhra–Odisha water dispute. Notice how tributary questions reward learning rivers in their basins.
Answer as per the official UPSC answer key.
Which one of the following pairs of islands is separated from each other by the ‘Ten Degree Channel’?
Answer (a) & explanation
The Ten Degree Channel runs along about 10° N and separates Little Andaman from Car Nicobar, so it divides the Andaman group from the Nicobar group (a). The other pairs have their own channels: the Great Channel lies between Great Nicobar and Sumatra (b); the Eight Degree Channel separates Minicoy from the Maldives (c); and the Sunda Strait separates Sumatra from Java (d).
The Nine Degree Channel separates Minicoy from the main Lakshadweep islands. Notice how these channels sit on busy sea lanes towards the Malacca Strait, which is why they matter for India's maritime security and trade.
Answer as per the official UPSC answer key.
Consider the following rivers :
- 1. Barak
- 2. Lohit
- 3. Subansiri
Which of the above flows/flow through Arunachal Pradesh?
Answer (b) & explanation
The Lohit and Subansiri flow through Arunachal Pradesh to join the Brahmaputra, so the answer is (b). The Barak rises in the Manipur hills, flows through Manipur, Mizoram and Assam's Cachar region, and enters Bangladesh as the Surma–Meghna, so options with 1 fail.
The Subansiri is the largest tributary of the Brahmaputra and hosts the Subansiri Lower hydroelectric project. The Lohit carries the Dhola–Sadiya (Bhupen Hazarika) bridge across it. Notice how hydropower in Arunachal links river geography to energy security and relations with China upstream.
Answer as per the official UPSC answer key.
Consider the following pairs :
| Hills | Region
| 1. Cardamom Hills | Coromandel Coast
| 2. Kaimur Hills | Konkan Coast
| 3. Mahadeo Hills | Central India
| 4. Mikir Hills | North-East India
Which of the above pairs are correctly matched?
Answer (c) & explanation
Pairs 3 and 4 are correct (c). The Mahadeo Hills, with Pachmarhi, are part of the Satpura range in central India. The Mikir Hills (Karbi Anglong) are in Assam in the North-East. The Cardamom Hills are in the southern Western Ghats on the Kerala–Tamil Nadu border, not the Coromandel coast. The Kaimur Hills are the eastern end of the Vindhyas in Madhya Pradesh, Uttar Pradesh and Bihar, not the Konkan coast.
Notice how matching hills to regions becomes easy once the major ranges are fixed on a mental map of India.
Answer as per the official UPSC answer key.
The Narmada river flows to the west, while most other large peninsular rivers flow to the east. Why?
- 1. It occupies a linear rift valley.
- 2. It flows between the Vindhyas and the Satpuras.
- 3. The land slopes to the west from Central India.
Select the correct answer using the codes given below.
Answer (a) & explanation
Statement 1 only is correct (a). The Narmada, like the Tapi, flows west because it follows a rift valley formed by faulting, so its course is set by that trough (1). Statement 2 is a fact, but it only describes where it flows, between the Vindhyas and the Satpuras, not why it flows west; UPSC treats it as not a reason. Statement 3 is wrong: the Peninsular plateau as a whole slopes east, which is why most rivers flow into the Bay of Bengal. So (b), (c) and (d) fail.
Notice the consequence: rift-valley rivers form estuaries, not deltas, and have few tributaries. The Sardar Sarovar dam is on the Narmada, and the river rises at Amarkantak. Trap: a true fact can still be the wrong reason.
Answer as per the official UPSC answer key.
When you travel in Himalayas, you will see the following :
- 1. Deep gorges
- 2. U-turn river courses
- 3. Parallel mountain ranges
- 4. Steep gradients causing land-sliding
Which of the above can be said to be the evidences for Himalayas being young fold mountains?
Answer (d) & explanation
All four are correct (d). The Himalayas are young fold mountains, still rising as the Indian plate pushes into Asia. Fast uplift makes rivers cut deep gorges (1), such as the Indus, Sutlej and Dihang gorges, and take sharp U-turns at the syntaxial bends (2). The parallel ranges, Shiwalik, Lesser and Greater Himalaya, are sharp-crested and little eroded (3). Steep, unstable slopes cause frequent landslides (4). So options (a), (b) and (c) leave out real evidence.
Notice the contrast: old mountains like the Aravallis are worn down and gentle. Frequent earthquakes are further evidence. The Joshimath subsidence (2023) and the 2025 Dharali flash flood show the risks of building on young slopes. Trap: rivers older than the mountains are called antecedent rivers.
Answer as per the official UPSC answer key.
Consider the following statements :
- 1. The duration of the monsoon decreases from southern India to northern India.
- 2. The amount of annual rainfall in the northern plains of India decreases from east to west.
Which of the statements given above is/are correct?
Answer (c) & explanation
Both statements are correct (c). The monsoon arrives first in Kerala around 1 June and withdraws from the south last, in October–December, while it reaches north-west India in July and leaves in September, so its duration decreases from south to north (1). In the northern plains, the Bay of Bengal branch loses moisture as it moves west, so annual rainfall decreases from east to west, from over 150 cm in West Bengal to under 50 cm in western Rajasthan (2). So (a), (b) and (d) fail.
Notice the related rule: rainfall also decreases inland from the Western Ghats, leaving a rain-shadow in the Deccan. The 2025 monsoon onset over Kerala came early, on 24 May. Trap: both are standard gradients.
Answer as per the official UPSC answer key.
The Brahmaputra, Irrawady and Mekong rivers originate in Tibet and flow through narrow and parallel mountain ranges in their upper reaches. Of these rivers, Brahmaputra makes a “U” turn in its course to flow into India. This “U” turn is due to
Answer (b) & explanation
Syntaxial bending of the young Himalaya is correct (b). At the eastern end of the Himalaya, near Namcha Barwa (7,782 m), the mountain chain bends sharply south in a hairpin called the eastern syntaxis, caused by the pressure of the Indian plate. The Tsangpo follows this bend, cuts the world's deepest gorge, and turns back as the Siang/Dihang, becoming the Brahmaputra in Assam. (a) and (c) are general statements that do not explain the specific U-turn. (d) fails because (a) is not the reason.
Notice the western twin: the Nanga Parbat syntaxis, where the Indus turns sharply. China began building a mega-dam on the Yarlung Tsangpo at Medog near this bend in July 2025, raising concerns in India. Trap: 'uplift' is too general.
Answer as per the official UPSC answer key.