UPSC Prelims PYQs with explanations
Real questions from official papers, mapped to syllabus topics. Attempt each one; the answer and the reason appear instantly.
Read the passage
Understanding of the role of biodiversity in the hydrological cycle enables better policy-making. The term biodiversity refers to the variety of plants, animals, microorganisms, and the ecosystems in which they occur. Water and biodiversity are interdependent. In reality, the hydrological cycle decides how biodiversity functions. In turn, vegetation and soil drive the movement of water. Every glass of water we drink has, at least in part, passed through fish, trees, bacteria, soil and other organisms. Passing through these ecosystems, it is cleansed and made fit for consumption. The supply of water is a critical service that the environment provides.
Which among the following is the most critical inference that can be made from the above passage ?
Answer (a) & explanation
The best inference is that biodiversity keeps nature's water cycle going (a). Step 1: the passage says vegetation and soil "drive the movement of water", and ecosystems cleanse it. So living things sustain nature's water recycling. Step 2: option (b) says we cannot get drinking water without living things. The passage says water passes through organisms "at least in part", so "cannot" overstates it. Step 3: option (c), about organisms interacting, is true but beside the point. Option (d) is about how life began, which the passage does not discuss.
Tip: pick the option that sums up the passage's link. Options that go further than the passage, like "cannot", are traps.
Answer as per the official UPSC answer key.
A and B walk around a circular park. They start at 8 a.m. from the same point in the opposite directions. A and B walk at a speed of 2 rounds per hour and 3 rounds per hour respectively. How many times shall they cross each other after 8.00 a.m. and before 9.30 a.m.?
Answer (a) & explanation
They cross each other 7 times (a). Step 1: they walk in opposite directions, so their speeds add: 2 + 3 = 5 rounds per hour. Together they cover one full round every 60 ÷ 5 = 12 minutes. So they meet every 12 minutes. Step 2: from 8:00 to 9:30 is 90 minutes. They meet at 8:12, 8:24, 8:36, 8:48, 9:00, 9:12 and 9:24. Step 3: the next meeting is at 9:36, which is too late. So they cross 7 times. Option (b), 6, misses one. Option (c), 5, uses 1 hour. Option (d), 8, counts 9:36.
Tip: in circular tracks, opposite directions add speeds and the same direction subtracts them.
Answer as per the official UPSC answer key.
The FAO accords the status of 'Globally Important Agricultural Heritage System (GIAHS)' to traditional agricultural systems. What is the overall goal of this initiative?
- 1. To provide modern technology, training in modern farming methods and financial support to local communities of identified GIAHS so as to greatly enhance their agricultural productivity
- 2. To identify and safeguard eco-friendly traditional farm practices and their associated landscapes, agricultural biodiversity and knowledge systems of the local communities
- 3. To provide Geographical Indication status to all the varieties of agricultural produce in such identified GIAHS
Select the correct answer using the code given below.
Answer (b) & explanation
Only statement 2 is correct (b). GIAHS, started by the FAO in 2002, aims to identify and safeguard traditional farming systems along with their landscapes, agro-biodiversity and local knowledge. Statement 1 is wrong because the idea is to conserve traditional practices, not to replace them with modern technology. Statement 3 is wrong because GI tags are given under national law (in India, the GI Act, 1999), not by GIAHS.
India's GIAHS sites are Koraput (Odisha), Kuttanad below-sea-level farming (Kerala) and Pampore saffron (Kashmir). Notice how this connects to in-situ conservation: protecting genes and knowledge in the living farms where they evolved, not just in seed banks.
Answer as per the official UPSC answer key.
The term 'Base Erosion and Profit Shifting' is sometimes seen in the news in the context of
Answer (b) & explanation
BEPS is about curbing tax avoidance by multinationals (b). Base Erosion and Profit Shifting means MNCs move profits to low-tax places, shrinking the tax base where they really do business. The OECD/G20 BEPS project gave 15 actions in 2015 to fight it. It has nothing to do with mining in backward areas (a), biopiracy of genetic resources (c), or environmental costs of projects (d).
India brought in the equalisation levy (2016) on digital ads and joined the Two-Pillar solution. Pillar Two sets a 15% global minimum corporate tax. India dropped its 6% levy on online ads from April 2025. Notice the overlap with GAAR and the Place of Effective Management rule, two domestic tools used against treaty shopping.
Answer as per the official UPSC answer key.
What was the main reason for the split in the Indian National Congress at Surat in 1907?
Answer (b) & explanation
The split came from the Extremists' lack of faith in the Moderates' methods (b). After the partition of Bengal (1905), Extremists led by Tilak, Lajpat Rai, Bipin Chandra Pal and Aurobindo wanted to spread swadeshi, boycott and national education across India. They had no faith in the Moderates' petition-and-prayer approach. At Surat (1907) they clashed over the president, Rash Behari Ghosh, and the session broke up. Minto's separate electorates (a) came only in 1909. The Muslim League (c) was founded in 1906 but did not cause the split. Aurobindo was never a presidential candidate (d); the Extremists wanted Lajpat Rai.
Notice the result: the British arrested Tilak (Mandalay, 1908). The two groups came back together at Lucknow in 1916.
Aurobindo was a leading Extremist, but the presidency dispute was a symptom, not the cause, of the split.
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Answer as per the official UPSC answer key.
Read the passage
Biomass as fuel for power, heat, and transport has the highest mitigation potential of all renewable sources. It comes from agriculture and forest residues as well as from energy crops. The biggest challenge in using biomass residues is a long-term reliable supply delivered to the power plant at reasonable costs; the key problems are logistical constraints and the costs of fuel collection. Energy crops, if not managed properly, compete with food production and may have undesirable impacts on food prices. Biomass production is also sensitive to the physical impacts of a changing climate.
Projections of the future role of biomass are probably overestimated, given the limits to the sustainable biomass supply, unless breakthrough technologies substantially increase productivity. Climate-energy models project that biomass use could increase nearly four-fold to around 150 — 200 exajoules, almost a quarter of world primary energy in 2050. However the maximum sustainable technical potential of biomass resources (both residues and energy crops) without disruption of food and forest resources ranges from 80 — 170 exajoules a year by 2050, and only part of this is realistically and economically feasible. In addition, some climate models rely on biomass-based carbon capture and storage, an unproven technology, to achieve negative emissions and to buy some time during the first half of the century.
Some liquid biofuels such as corn-based ethanol, mainly for transport, may aggravate rather than ameliorate carbon emissions on a life-cycle basis. Second generation biofuels, based on ligno-cellulosic feedstocks — such as straw, bagasse, grass and wood — hold the promise of sustainable production that is high-yielding and emit low levels of greenhouse gases, but these are still in the R & D stage.
Which of the following can lead to food security problem ?
- 1. Using agricultural and forest residues as feedstock for power generation
- 2. Using biomass for carbon capture and storage
- 3. Promoting the cultivation of energy crops
Select the correct answer using the code given below :
Answer (b) & explanation
Only promoting energy crops threatens food security (b). Step 1: the passage says energy crops "compete with food production and may have undesirable impacts on food prices". So statement 3 is a food security risk. Step 2: agricultural and forest residues (statement 1) are left over after the harvest. Using them takes no food away. Step 3: carbon capture and storage with biomass (statement 2) is described as an unproven technology. It is a climate issue, not a food issue. So options (a), (c) and (d) fail.
Tip: link each statement to the exact problem the passage pins on it. Residues and waste are usually shown as the "safe" choice in biomass passages.
Answer as per the official UPSC answer key.
When three friends A, B and C met, it was found that each of them wore an outer garment of a different colour. In random order, the garments are: jacket, sweater and tie; and the colours are: blue, white and black. Their surnames in random order are: Ribeiro, Kumar and Singh. Further, we know that :
- 1. neither B nor Ribeiro wore a white sweater
- 2. C wore a tie
- 3. Singh's garment was not white
- 4. Kumar does not wear a jacket
- 5. Ribeiro does not like to wear the black colour
- 6. Each of the friends wore only one outer garment of only one colour
What is C's surname ?
Answer (a) & explanation
C's surname is Ribeiro (a). Step 1: someone wore the white sweater. It was not B (clue 1) and not C, who wore the tie (clue 2). So A wore the white sweater. Step 2: A is not Ribeiro (clue 1) and not Singh, whose garment was not white (clue 3). So A is Kumar. Step 3: clue 1 names B and Ribeiro as two different people. So B is not Ribeiro, which makes C Ribeiro and B Singh. Options (b) Kumar and (c) Singh belong to A and B. Option (d) fails because the clues settle it.
Tip: clues like "neither B nor Ribeiro" quietly tell you B and Ribeiro are different people. Use such hidden facts.
Answer as per the official UPSC answer key.
The term ‘Intended Nationally Determined Contributions’ is sometimes seen in the news in the context of
Answer (b) & explanation
Intended Nationally Determined Contributions were climate pledges countries set for themselves before the Paris Agreement (2015), so the term relates to combating climate change (b). Once a country ratified the Agreement, its INDC became its NDC. The term has nothing to do with refugee pledges (a), AIIB capital (c) or the SDGs (d).
India pledged to cut emissions intensity of GDP by 33–35% from 2005 levels by 2030, and raised this to 45% in 2022, along with 50% of power capacity from non-fossil sources by 2030 and net zero by 2070. Notice how Paris replaced top-down targets with nationally decided ones.
Answer as per the official UPSC answer key.
Banjaras during the medieval period of Indian history were generally
Answer (d) & explanation
Banjaras were mainly traders and carriers (d). They moved in large bullock caravans called tanda, carrying grain, salt and other goods over long distances. They were not chiefly agriculturists (a), warriors (b) or weavers (c), though they served armies as suppliers.
Alauddin Khalji used Banjaras to bring grain to Delhi's markets as part of his price controls. Jahangir described their caravans in his memoirs, and Mughal armies relied on them for supplies on campaign. Notice how such mobile traders knit together a vast internal market long before railways, a point that often appears in questions on medieval trade.
Answer as per the official UPSC answer key.
What is/are the purpose/purposes of Government's 'Sovereign Gold Bond Scheme' and 'Gold Monetization Scheme'?
- 1. To bring the idle gold lying with Indian households into the economy
- 2. To promote FDI in the gold and jewellery sector
- 3. To reduce India's dependence on gold imports
Select the correct answer using the code given below.
Answer (c) & explanation
Statements 1 and 3 are correct (c). Both schemes were launched in November 2015 to cut physical gold imports, which widen India's current account deficit. The Gold Monetisation Scheme lets households and temples deposit idle gold with banks and earn interest (1). Sovereign Gold Bonds, issued by the RBI for the government, give a paper alternative with 2.5% interest and gains linked to the gold price (3). Statement 2 is wrong because neither scheme has anything to do with FDI in jewellery.
The government stopped new SGB issues in 2025 because costs rose with the gold price, and medium- and long-term GMS deposits also ended. Notice how gold ETFs and IIBX (GIFT City) are the other parts of gold policy.
Answer as per the official UPSC answer key.
Read the passage
Accountability, or the lack of it, in governance generally, and civil services, in particular, is a major factor underlying the deficiencies in governance and public administration. Designing an effective framework for accountability has been a key element of the reform agenda. A fundamental issue is whether civil services should be accountable to the political executive of the day or to society at large. In other words, how should internal and external accountability be reconciled ? Internal accountability is sought to be achieved by internal performance monitoring, official supervision by bodies like the Central Vigilance Commission and Comptroller and Auditor General, and judicial review of executive decisions. Articles 311 and 312 of the Indian Constitution provide job security and safeguards to the civil services, especially the All India Services. The framers of the Constitution had envisaged that provision of these safeguards would result in a civil service that is not totally subservient to the political executive but will have the strength to function in larger public interest. The need to balance internal and external accountability is thus built into the Constitution. The issue is where to draw the line. Over the years, the emphasis seems to have tilted in favour of greater internal accountability of the civil services to the political leaders of the day who in turn are expected to be externally accountable to the society at large through the election process. This system for seeking accountability to society has not worked out, and has led to several adverse consequences for governance.
Some special measures can be considered for improving accountability in civil services. Provisions of articles 311 and 312 should be reviewed and laws and regulations framed to ensure external accountability of civil services. The proposed Civil Services Bill seeks to address some of these requirements. The respective roles of professional civil services and the political executive should be defined so that professional managerial functions and management of civil services are depoliticized. For this purpose, effective statutory civil service boards should be created at the centre and in the states. Decentralization and devolution of authority to bring government and decision making closer to the people also helps to enhance accountability.
According to the passage, which of the following factor/factors led to the adverse consequences for governance/public administration ?
- 1. Inability of civil services to strike a balance between internal and external accountabilities
- 2. Lack of sufficient professional training to the officers of All India Services
- 3. Lack of proper service benefits in civil services
- 4. Lack of Constitutional provisions to define the respective roles of professional civil services vis-a-vis political executive in this context
Select the correct answer using the code given below :
Answer (c) & explanation
The answer is 1 and 4 only (c). Step 1: the passage says the tilt towards internal accountability to political leaders "has led to several adverse consequences". That is the failure to balance internal and external accountability, so statement 1 is right. Step 2: it also says the roles of civil servants and the political executive should be defined, which means they are not clearly defined now. So statement 4 is right. Step 3: training of officers (2) and service benefits (3) are never mentioned. So options (a), (b) and (d) fail.
Tip: in "according to the passage" questions, tick a statement only if you can point to a line that supports it. Sensible ideas from outside the passage do not count.
Answer as per the official UPSC answer key.
The monthly average salary paid to all the employees of a company was Rs. 5000. The monthly average salary paid to male and female employees was Rs. 5200 and Rs. 4200 respectively. Then the percentage of males employed in the company is :
Answer (b) & explanation
Males are 80% of the staff (b). Step 1: use alligation. The overall average is Rs 5000. Males earn Rs 5200, which is 200 above it. Females earn Rs 4200, which is 800 below it. Step 2: the counts are in the reverse ratio of these gaps. Males : females = 800 : 200 = 4 : 1. Step 3: males = 4 out of 5 = 80%. Option (a), 75%, would give an average of 4950. Options (c) and (d) give averages above 5000.
Tip: in mixture averages, the bigger group sits closer to the overall average. Since 5000 is much closer to 5200, males must be the large majority.
Answer as per the official UPSC answer key.
Read the passage
All humans digest mother’s milk as infants, but until cattle began being domesticated 10,000 years ago, children once weaned no longer needed to digest milk. As a result, they stopped making the enzyme lactase, which breaks down the sugar lactose into simple sugars. After humans began herding cattle, it became tremendously advantageous to digest milk, and lactose tolerance evolved independently among cattle herders in Europe, the middle East and Africa. Groups not dependant on cattle, such as the Chinese and Thai, remain lactose intolerant.
Which among the following is the most logical assumption that can be made from the above passage ?
Answer (b) & explanation
The logical assumption is that a lasting change in food habits can bring a genetic change (b). Step 1: the passage says herding made milk a lasting food, and lactose tolerance evolved among herders. So a long-term diet change led to a genetic change. That is option (b). Step 2: option (a), about domestication 10,000 years ago, restates a fact rather than an assumption. Step 3: option (c) says only lactose-tolerant people get simple sugars, and option (d) says intolerant people cannot digest any dairy. Both overgeneralise; many people digest curd and cheese.
Tip: an assumption is the hidden link the author needs. Facts already stated in the passage are not assumptions.
Answer as per the official UPSC answer key.
With reference to the cultural history of medieval India, consider the following statements :
- 1. Siddhas (Sittars) of Tamil region were monotheistic and condemned idolatry.
- 2. Lingayats of Kannada region questioned the theory of rebirth and rejected the caste hierarchy.
Which of the statements given above is/are correct?
Answer (c) & explanation
Both are correct (c). The Siddhas (Sittars) were Tamil mystics who believed in one god and mocked idol worship, rituals and caste (1). The Lingayats or Virashaivas, founded by Basavanna in the 12th century, worshipped Shiva alone through the personal ishtalinga, rejected caste hierarchy and questioned the theory of rebirth (2). They also allowed widow remarriage.
Basavanna's vachanas, short poems in Kannada, spread these ideas, and the Anubhava Mantapa was a hall for spiritual debate. Notice how these movements challenged hierarchy long before modern social reform.
Answer as per the official UPSC answer key.
With reference to the religious history of India, consider the following statements :
- 1. The concept of Bodhisattva is central to Hinayana sect of Buddhism.
- 2. Bodhisattva is a compassionate one on his way to enlightenment.
- 3. Bodhisattva delays achieving his own salvation to help all sentient beings on their path to it.
Which of the statements given above is/are correct?
Answer (b) & explanation
Statements 2 and 3 are correct (b). Statement 1 is wrong: the Bodhisattva ideal is central to Mahayana, not Hinayana. Hinayana (Theravada) aims at becoming an arhat, one who wins his own liberation. A Bodhisattva is a compassionate being on the path to enlightenment (2) who delays his own nirvana to help all sentient beings reach it (3).
Famous Bodhisattvas include Avalokiteshvara, embodying compassion, painted at Ajanta as Padmapani, and Maitreya, the future Buddha. Mahayana grew strong under Kanishka and the Fourth Buddhist Council. Notice how the shift from personal salvation to compassion for all shaped Buddhism across Tibet, China and Japan.
Answer as per the official UPSC answer key.
'European Stability Mechanism', sometimes seen in the news, is an
Answer (b) & explanation
The ESM lends to eurozone countries in financial trouble (b). The European Stability Mechanism was set up in 2012 as a permanent rescue fund for the eurozone after the sovereign debt crisis. It is based in Luxembourg and replaced the temporary EFSF. It lends to member states, with conditions on reforms. Greece, Spain, Cyprus and Portugal used it or its predecessor. It does not deal with refugees (a), which is FRONTEX's area. It does not handle trade agreements (c), which is the European Commission's job, and it does not settle disputes among members (d), which goes to the EU Court of Justice.
Notice the comparison: the ESM is like a regional IMF for the euro area, and it offers loans in exchange for strict reforms.
Answer as per the official UPSC answer key.
Five people A, B, C, D and E are seated about a round table. Every chair is spaced equidistant from adjacent chairs.
- (i) C is seated next to A
- (ii) A is seated two seats from D
- (iii) B is not seated next to A
On the basis of above information, which of the following must be true ?
- 1. D is seated next to B
- 2. E is seated next to A
- 3. D and C are separated by two seats
Select the correct answer using the code given below :
Answer (b) & explanation
Statements 1 and 2 must be true (b). Step 1: with five seats, A has two neighbours. B cannot sit next to A, and D sits two seats away, so not next to A either. So A's neighbours are C and E. Statement 2 is true. Step 2: the two seats that are not next to A are next to each other. B and D take them. So D sits next to B, and statement 1 is true. Step 3: the order could be A, C, D, B, E or A, C, B, D, E. In the second case D and C are not two seats apart. So statement 3 need not be true.
Tip: in seating puzzles, place the person with the most rules first. Then try every arrangement left before saying something "must" be true.
Answer as per the official UPSC answer key.
Read the passage
In the last decade, the banking sector has been restructured with a high degree of automation and products that mainly serve middle-class and upper middle-class society. Today there is a need for a new agenda for the banking and non-banking financial services that does not exclude the common man.
Which one of the following is the message that is essentially implied in the above passage ?
Answer (d) & explanation
The implied message is the need to promote financial inclusion (d). Step 1: the passage says banking mainly serves the middle classes, and a new agenda must not "exclude the common man". That is financial inclusion. Step 2: option (a), more automation, is part of the problem the passage describes, not the cure. Step 3: option (b), restructuring the whole public finance system, goes beyond banking. Option (c), integrating banks and non-banks, is not raised.
Tip: financial inclusion means bringing the poor and rural people into banking: accounts, credit and insurance. Schemes like Jan Dhan accounts are real-life examples.
Answer as per the official UPSC answer key.
W can do 25% of a work in 30 days, X can do 1/4 of the work in 10 days, Y can do 40% of the work in 40 days and Z can do 1/3 of the work in 13 days. Who will complete the work first?
Answer (d) & explanation
Z will finish first (d). Step 1: work out each person's time for the whole job. W does 25% in 30 days, so the whole job takes 4 × 30 = 120 days. X does 1/4 in 10 days, so 40 days. Step 2: Y does 40% in 40 days, so 40 ÷ 0.4 = 100 days. Z does 1/3 in 13 days, so 3 × 13 = 39 days. Step 3: the shortest time is Z's 39 days. Option (b), X, is close at 40 days but slower. Options (a) W and (c) Y are much slower.
Tip: put everyone on the same base, the full job, before comparing. Close numbers like 39 and 40 are the setter's trap.
X looks fastest at a glance. Z's 1/3 in 13 days is just quicker.
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.