UPSC Prelims PYQs with explanations
Real questions from official papers, mapped to syllabus topics. Attempt each one; the answer and the reason appear instantly.
Consider the following statements :
- 1. The India Sanitation Coalition is a platform to promote sustainable sanitation and is funded by the Government of India and the World Health Organization.
- 2. The National Institute of Urban Affairs is an apex body of the Ministry of Housing and Urban Affairs in Government of India and provides innovative solutions to address the challenges of Urban India.
Which of the statements given above is/are correct ?
Answer (d) & explanation
Neither statement is correct (d). Statement 1 is wrong: the India Sanitation Coalition was launched in 2015 at FICCI as a platform where companies, NGOs, donors and government work together on sanitation. It is not funded by the Government of India and the WHO. Statement 2 is wrong: the National Institute of Urban Affairs (1976) is an autonomous research and training institute that supports the Ministry of Housing and Urban Affairs; it is not the Ministry's apex body. It runs studies and projects such as the Smart Cities and climate work.
Notice the trap: UPSC slips in words like "funded by" or "apex body" to make a mostly true line wrong. The matching government mission is the Swachh Bharat Mission, launched on 2 October 2014.
Answer as per the official UPSC answer key.
Read the passage
The main threat to maintaining progress in human development comes from the increasingly evident unsustainability of production and consumption patterns. Current production models rely heavily on fossil fuels. We now know that this is unsustainable because the resources are finite. The close link between economic growth and greenhouse gas emissions needs to be severed for human development to become truly sustainable. Some developed countries have begun to alleviate the worst effects by expanding recycling and investing in public transport and infrastructure. But most developing countries are hampered by the high costs and low availability of clean energy sources. Developed countries need to support developing countries’ transition to sustainable human development.
Consider the following statements :
Developed countries can support developing countries’ transition to sustainable human development by
- 1. making clean energy sources available at low cost
- 2. providing loans for improving their public transport at nominal interest rates
- 3. encouraging them to change their production and consumption patterns
Which of the statements given above is/are correct?
Answer (b) & explanation
Statements 1 and 2 are correct (b). Step 1: the passage says developing countries face "high costs and low availability of clean energy". So making clean energy cheap and available helps them (1). Step 2: it says developed countries have eased harm by investing in public transport. Low-interest loans for this are real support (2). Step 3: statement 3, merely encouraging change, gives no material help. The passage asks developed countries to "support" the transition. So options (a), (c) and (d) fail.
Tip: "support" in such passages means money, technology or cheaper access. Advice alone is not support. India's climate stance also stresses finance and technology transfer from developed nations.
Answer as per the official UPSC answer key.
Read the passage
With steady economic growth, higher literacy and increasing skill levels, the number of Indian middle-class families has gone up exponentially. Direct results of the affluence have been changes in dietary patterns and energy consumption levels. People have moved to a higher protein-based diet like milk products, fish and meat, all of which need significantly more water to produce than cereal-based diets. Increasing use of electronic and electric machines/gadgets and motor vehicles needs more and more energy and generation of energy needs water.
Which one of the following statements best reflects the crux of the passage?
Answer (d) & explanation
The crux is that India's water management must change dramatically (d). Step 1: the passage says growing affluence changed diets toward milk, fish and meat, which need much more water than cereals. Step 2: it says more gadgets and vehicles need more energy, and making energy needs water. Both changes push water demand up, so water management must change. That is (d). Step 3: option (a) asks people to go back to cereal diets, which the passage does not suggest. Option (b) misses water. Option (c) is too general.
Tip: find the common thread in the examples. Diet and energy both lead to one word here: water.
Answer as per the official UPSC answer key.
Let p be a two-digit number and q be the number consisting of same digits written in reverse order. If p × q = 2430, then what is the difference between p and q?
Answer (d) & explanation
The difference is 9 (d). Step 1: p and q use the same two digits in reverse. Their product 2430 ends in 0, so one digit must be 5 and the other even (or one digit 0, which is not possible here). Step 2: try 45 × 54 = 2430. It works. Step 3: the difference is 54 − 45 = 9. Options (a), (b) and (c) do not fit.
Tip: a two-digit number and its reverse always differ by a multiple of 9 (9 × the difference of digits). Here the digits differ by 1, so the gap is 9.
Answer as per the official UPSC answer key.
With reference to Deputy Speaker of Lok Sabha, consider the following statements :
- 1. As per the Rules of Procedure and Conduct of Business in Lok Sabha, the election of Deputy Speaker shall be held on such date as the Speaker may fix.
- 2. There is a mandatory provision that the election of a candidate as Deputy Speaker of Lok Sabha shall be from either the principal opposition party or the ruling party.
- 3. The Deputy Speaker has the same power as of the Speaker when presiding over the sitting of the House and no appeal lies against his rulings.
- 4. The well established parliamentary practice regarding the appointment of Deputy Speaker is that the motion is moved by the Speaker and duly seconded by the Prime Minister.
Which of the statements given above are correct?
Answer (a) & explanation
Statements 1 and 3 are correct (a). Statement 1 is right: under Rule 8 of the Lok Sabha's Rules of Procedure, the election of the Deputy Speaker is held on a date the Speaker fixes. Statement 2 is wrong: no rule ties the post to the opposition or the ruling party; giving it to the opposition is only a custom. Statement 3 is right: when presiding, the Deputy Speaker has the Speaker's full powers, and no appeal lies against his rulings. Statement 4 is wrong: the motion is moved by a member, not by the Speaker.
Notice that Article 93 says the Lok Sabha "shall" choose a Deputy Speaker, yet the post stayed vacant through the whole 17th Lok Sabha (2019–24). The Deputy Speaker sends any resignation to the Speaker.
"mandatory provision" for what is only a convention.
Answer as per the official UPSC answer key.
In medieval India, the term “Fanam” referred to:
Answer (b) & explanation
Fanam was a coin (b). The fanam (Tamil and Malayalam panam) was a small gold coin of South India. It was struck by Vijayanagara, the Malabar rulers and later by the European companies at Madras and Pondicherry. Foreign visitors such as Abdur Razzaq and the Portuguese described it as the common small unit; bigger values were the pagoda or varaha (hun). It was not a cloth (a), an ornament (c) or a weapon (d), though its tiny size sometimes made it look like a bead.
Notice that the word lives on: panam still means money in Tamil and Malayalam. UPSC likes such coin terms: the tanka and jital of the Delhi Sultanate, the dam and rupiya of Sher Shah, and the dinara of the Guptas.
Answer as per the official UPSC answer key.
With reference to the United Nations Convention on the Law of Sea, consider the following statements :
- 1. A coastal state has the right to establish the breadth of its territorial sea up to a limit not exceeding 12 nautical miles, measured from baseline determined in accordance with the convention.
- 2. Ships of all states, whether coastal or land-locked, enjoy the right of innocent passage through the territorial sea.
- 3. The Exclusive Economic Zone shall not extend beyond 200 nautical miles from the baseline from which the breadth of the territorial sea is measured.
Which of the statements given above are correct ?
Answer (d) & explanation
All three statements are correct (d). Statement 1 is right: under UNCLOS (1982), a coastal state can fix its territorial sea up to 12 nautical miles from the baseline, where it has full sovereignty. Statement 2 is right: ships of all states, coastal or landlocked, have the right of innocent passage through it, as long as they do not threaten the coastal state. Statement 3 is right: the Exclusive Economic Zone cannot go beyond 200 nautical miles from the baseline; there the coastal state owns fish, oil and minerals.
Notice the other zones: the contiguous zone goes to 24 nm, for customs and immigration control, and the continental shelf can stretch to 350 nm. Beyond lie the high seas, now covered by the BBNJ treaty.
Answer as per the official UPSC answer key.
Read the passage
The poverty line is quite unsatisfactory when it comes to grasping the extent of poverty in India. It is not only because of its extremely narrow definition of ‘who is poor’ and the debatable methodology used to count the poor, but also because of a more fundamental assumption underlying it. It exclusively relies on the notion of poverty as insufficient income or insufficient purchasing power. One can better categorize it by calling it income poverty. If poverty is ultimately about deprivations affecting human well-being, then income poverty is only one aspect of it. Poverty of a life, in our view, lies not merely in the impoverished state in which the person actually lives, but also in the lack of real opportunity given by social constraints as well as personal circumstances—to choose other types of living. Even the relevance of low incomes, meagre possessions, and other aspects of what are standardly seen as economic poverty relate ultimately to their role in curtailing capabilities, i.e., their role in severely restricting the choices people have to lead variable and valued lives.
Why is income poverty only one measure of counting the ‘poor’ ?
Answer (a) & explanation
Income poverty is only one measure because it covers only one kind of deprivation (a). Step 1: the passage says poverty is about all "deprivations affecting human well-being". Income poverty is "only one aspect" of it. So it ignores other deprivations. That is (a). Step 2: option (b) says other deprivations have nothing to do with income. But the passage says low income matters because it curtails capabilities. Step 3: options (c) and (d) talk about time (permanent, at one point). The passage says nothing about time.
Tip: options with "nothing to do with" are absolute. Check whether the passage links the two ideas; here it clearly does.
Answer as per the official UPSC answer key.
Five friends P, Q, X, Y and Z purchased some notebooks. The relevant information is given below :
- 1. Z purchased 8 notebooks more than X did.
- 2. P and Q together purchased 21 notebooks.
- 3. Q purchased 5 notebooks less than P did.
- 4. X and Y together purchased 28 notebooks.
- 5. P purchased 5 notebooks more than X did.
If each notebook is priced ₹ 40, then what is the total cost of all the notebooks?
Answer (a) & explanation
The total cost is ₹ 2,600 (a). Step 1: P + Q = 21 and Q = P − 5. So 2P − 5 = 21, giving P = 13 and Q = 8. Step 2: P bought 5 more than X, so X = 8. Z bought 8 more than X, so Z = 16. X + Y = 28, so Y = 20. Step 3: total = 13 + 8 + 8 + 20 + 16 = 65 notebooks. 65 × ₹ 40 = ₹ 2,600. Options (b), (c) and (d) come from wrong values.
Tip: start with the pair of equations that has only two unknowns (P and Q). Each answer then unlocks the next person.
Answer as per the official UPSC answer key.
There are 9 cups placed on a table arranged in equal number of rows and columns out of which 6 cups contain coffee and 3 cups contain tea. In how many ways can they be arranged so that each row should contain at least one cup of coffee?
Answer (d) & explanation
There are 81 ways (d). Step 1: the cups form a 3 × 3 grid. Placing the 3 tea cups decides everything. The number of ways to pick 3 places from 9 = 9 × 8 × 7 ÷ (3 × 2 × 1) = 84. Step 2: a row has no coffee only if all 3 tea cups fill that one row. This can happen in 3 ways (one per row). Step 3: 84 − 3 = 81. Options (a), (b) and (c) miscount.
Tip: for "at least one" conditions, count all cases and subtract the bad ones. It is usually easier than counting the good ones directly.
Answer as per the official UPSC answer key.
Consider the following :
- 1. Aarogya Setu
- 2. CoWIN
- 3. DigiLocker
- 4. DIKSHA
Which of the above are built on top of open-source digital platforms ?
Answer (d) & explanation
All four are built on open-source platforms (d). All four are part of India's digital public infrastructure, built on open-source code and open standards. Item 1 is right: Aarogya Setu, the COVID contact-tracing app, made its code open source in 2020. Item 2 is right: CoWIN, the vaccine registration platform, became an open-source stack (DIVOC) offered to other countries. Item 3 is right: DigiLocker stores official documents digitally on open standards. Item 4 is right: DIKSHA, the school learning platform, is built on Sunbird, an open-source framework.
Notice the India Stack: Aadhaar, UPI, DigiLocker and consent-based data sharing. India pushed DPI globally during its G20 presidency (2023), with the Global DPI Repository.
Answer as per the official UPSC answer key.
With reference to the 'Banks Board Bureau (BBB)', which of the following statements are correct ?
- 1. The Governor of RBI is the Chairman of BBB.
- 2. BBB recommends for the selection of heads for Public Sector Banks.
- 3. BBB helps the Public Sector Banks in developing strategies and capital raising plans.
Select the correct answer using the code given below :
Answer (b) & explanation
Statements 2 and 3 are correct (b). The Banks Board Bureau was set up in 2016 under the Indradhanush plan to clean up how public sector banks were run. Statement 2 is right: it recommended heads and whole-time directors of public sector banks and state-run financial institutions. Statement 3 is right: it advised these banks on strategy, governance and capital raising. Statement 1 is wrong: its chairman was an eminent professional, the first being former CAG Vinod Rai, not the RBI Governor.
Notice that in 2022 the BBB was replaced by the Financial Services Institutions Bureau (FSIB), which now also selects heads of public sector insurance companies. Indradhanush stood for seven reforms: Appointments, BBB, Capitalisation, De-stressing, Empowerment, Accountability and Governance.
the RBI Governor heads many bodies, so statement 1 looks safe. BBB was deliberately kept independent of the regulator.
Answer as per the official UPSC answer key.
Which one of the following statements best describes the role of B cells and T cells in the human body ?
Answer (d) & explanation
B cells and T cells protect the body from pathogens (d). B and T lymphocytes are white blood cells that carry out adaptive immunity, which targets particular germs. B cells make antibodies that tag germs. Cytotoxic T cells kill infected cells, and helper T cells organise the whole response. Both keep a memory of past germs, which is why vaccines work. Option (a) is wrong: allergies come from an overreaction of the immune system, not protection from it. Option (b) is wrong: pain and inflammation are eased by drugs like painkillers. Option (c) is wrong: these cells drive immunity; they do not suppress it.
Notice that HIV attacks helper T cells (CD4). CAR-T therapy, now made in India, reprograms a patient's T cells to fight cancer.
Answer as per the official UPSC answer key.
The letters A, B, C, D and E are arranged in such a way that there are exactly two letters between A and E. How many such arrangements are possible?
Answer (c) & explanation
There are 24 arrangements (c). Step 1: five places in a row. With exactly two letters between them, A and E can be at places (1, 4) or (2, 5). Step 2: in each pair, A and E can swap. So 2 pairs × 2 = 4 ways to place A and E. Step 3: the other three letters fill the three free places in 3 × 2 × 1 = 6 ways. Total = 4 × 6 = 24. Options (a), (b) and (d) miss the swap or the extra pair.
Tip: place the restricted letters first, remember they can swap, then arrange the rest freely.
Answer as per the official UPSC answer key.
There are eight equidistant points on a circle. How many right-angled triangles can be drawn using these points as vertices and taking the diameter as one side of the triangle?
Answer (a) & explanation
24 right-angled triangles can be drawn (a). Step 1: an angle in a semicircle is always a right angle. So any triangle with a diameter as one side is right-angled. Step 2: eight equally spaced points form 4 diameters (each point has one opposite point). Step 3: each diameter can join any of the other 6 points to make a triangle. 4 × 6 = 24. Options (b), (c) and (d) miscount the diameters or the third points.
Tip: remember the circle rule: the angle in a semicircle is 90°. It turns this geometry question into simple counting.
Answer as per the official UPSC answer key.
Which one of the following situations best reflects "Indirect Transfers" often talked about in media recently with reference to India ?
Answer (d) & explanation
Indirect transfer means shares abroad deriving value from Indian assets (d). An indirect transfer happens when shares of a foreign company change hands abroad, but those shares get their substantial value from assets located in India. India claims the right to tax the gain. Options (a) and (b) describe ordinary cross-border investment and taxing of profits. Option (c) describes a direct sale of foreign assets by an Indian firm.
Notice the Vodafone case: its 2007 purchase of Hutchison's Indian business through a Cayman Islands company led to a tax demand. The Supreme Court ruled for Vodafone in 2012, and the government then passed a retrospective tax amendment. The Taxation Laws (Amendment) Act, 2021 withdrew that retrospective tax, ending the Cairn dispute as well.
Answer as per the official UPSC answer key.
Consider the following statements :
- 1. “The Climate Group” is an international non-profit organization that drives climate action by building large networks and runs them.
- 2. The International Energy Agency in partnership with the Climate Group launched a global initiative “EP100”.
- 3. EP100 brings together leading companies committed to driving innovation in energy efficiency and increasing competitiveness while delivering on emission reduction goals.
- 4. Some Indian companies are members of EP100.
- 5. The International Energy Agency is the Secretariat to the “Under2 Coalition”.
Which of the statements given above are correct ?
Answer (b) & explanation
Statements 1, 3 and 4 are correct (b). Statement 1 is right: The Climate Group is an international non-profit that builds and runs large networks for climate action, such as RE100 for renewable power. Statement 3 is right: EP100 gathers companies that pledge to use energy more efficiently, gaining competitiveness while cutting emissions. Statement 4 is right: Indian firms such as Mahindra are members. Statement 2 is wrong: EP100 was launched with the Alliance to Save Energy, not the IEA. Statement 5 is wrong: The Climate Group itself is the secretariat of the Under2 Coalition of state and regional governments.
Notice EV100 for electric vehicles, another Climate Group network. India's own efficiency agency is the Bureau of Energy Efficiency (2002).
Answer as per the official UPSC answer key.
Which one of the following has been constituted under the Environment (Protection) Act, 1986 ?
Answer (c) & explanation
The Central Ground Water Authority was set up under the Environment (Protection) Act (c). The Central Ground Water Authority came in 1997 under Section 3(3) of the Environment (Protection) Act, 1986, after a Supreme Court order, to regulate and control groundwater use. It issues No Objection Certificates for drawing groundwater and notifies over-exploited areas. Option (a) is wrong: the Central Water Commission dates from 1945 and is an attached office under the Jal Shakti Ministry. Option (b) is wrong: the Central Ground Water Board is a survey and research body. Option (d) is wrong: the National Water Development Agency (1982) is a society that plans river linking.
Notice that India is the world's largest user of groundwater, which is why the Atal Bhujal Yojana targets falling water tables.
CGWB and CGWA sound alike. The Board studies groundwater; the Authority regulates it.
Answer as per the official UPSC answer key.
Read the passage
Unless the forces and tendencies which are responsible for destroying the country’s environment are checked in the near future and afforestation of denuded areas is taken up on a massive scale, the harshness of the climatic conditions and soil erosion by wind and water will increase to such an extent that agriculture, which is the mainstay of our people, will gradually become impossible. The desert countries of the world and our own desert areas in Rajasthan are a grim reminder of the consequences of large-scale deforestation. Pockets of desert-like landscape are now appearing in other parts of the country including the Sutlej-Ganga Plains and the Deccan Plateau. Where only a few decades back there used to be lush green forests with perennial streams and springs, there is only brown earth, bare of vegetation, without any water in the streams and springs except in the rainy season.
According to the passage given above, deforestation and denudation will ultimately lead to which of the following?
- 1. Depletion of soil resource
- 2. Shortage of land for the common man
- 3. Lack of water for cultivation
Select the correct answer using the code given below.
Answer (c) & explanation
Statements 1 and 3 are the outcomes (c). Step 1: the passage warns of "soil erosion by wind and water", which depletes the soil (1). Step 2: it describes streams and springs without water except in the rains. So water for farming runs short (3). Step 3: a shortage of land for the common man (2) is never mentioned. The passage talks of land turning to desert, not of people lacking land. So options (a), (b) and (d) fail.
Tip: deforestation leads to desertification. Note the passage's examples: Rajasthan's desert, and pockets of desert-like land in the Sutlej-Ganga plains and the Deccan.
Answer as per the official UPSC answer key.
How many seconds in total are there in x weeks, x days, x hours, x minutes and x seconds?
Answer (d) & explanation
The total is 694861x seconds (d). Step 1: 1 week = 604800 s, 1 day = 86400 s, 1 hour = 3600 s, 1 minute = 60 s, plus 1 s. Step 2: add them: 604800 + 86400 + 3600 + 60 + 1 = 694861. So the total is 694861x. Step 3: options (a) and (b) leave out the week. Option (c), 694860x, forgets the last x seconds.
Tip: a quick check: "+ x seconds" makes the answer end in 1, which leaves (b) or (d). One week alone is over 6 lakh seconds, so (d).
Answer as per the official UPSC answer key.