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
Historically, the biggest challenge to world agriculture has been to achieve a balance between demand for and supply of food. At the level of individual countries, the demand-supply balance can be a critical policy issue for a closed economy, especially if it is a populous economy and its domestic agriculture is not growing sufficiently enough to ensure food supplies, on an enduring basis; it is not so much and not always, of a constraint for an open, and growing economy, which has adequate exchange surpluses to buy food abroad. For the world as a whole, supply-demand balance is always an inescapable prerequisite for warding off hunger and starvation. However, global availability of adequate supply does not necessarily mean that food would automatically move from countries of surplus to countries of deficit if the latter lack in purchasing power. The uneven distribution of hunger, starvation, under- or malnourishment, etc., at the world-level, thus owes itself to the presence of empty-pocket hungry mouths, overwhelmingly confined to the underdeveloped economies. Inasmuch as ‘a two-square meal’ is of elemental significance to basic human existence, the issue of worldwide supply of food has been gaining significance, in recent times; both because the quantum and the composition of demand has been undergoing big changes, and because, in recent years, the capabilities of individual countries to generate uninterrupted chain of food supplies have come under strain. Food production, marketing and prices, especially price-affordability by the poor in the developing world, have become global issues that need global thinking and global solutions.
According to the above passage, the biggest challenge to world agriculture is :
Answer (d) & explanation
The biggest challenge is to balance the demand for and supply of food (d). Step 1: the first sentence says: "the biggest challenge to world agriculture has been to achieve a balance between demand for and supply of food". Option (d) matches it word for word. Step 2: option (a), finding land and expanding food processing, is not called the biggest challenge. Step 3: option (b), ending hunger in poor countries, is a result of the imbalance, not the challenge named. Option (c), balancing food and non-food production, is not discussed.
Tip: when the passage states the answer directly, pick the option closest to its words. Do not overthink "biggest challenge" questions.
Answer as per the official UPSC answer key.
With reference to 'Pradhan Mantri Fasal Bima Yojana', consider the following statements
- 1. Under this scheme, farmers will have to pay a uniform premium of two percent for any crop they cultivate in any season of the year.
- 2. This scheme covers post-harvest losses arising out of cyclones and unseasonal rains.
Which of the statements given above is/are correct?
Answer (b) & explanation
Only statement 2 is correct (b). Under PMFBY (2016), the farmer's premium is 2% for kharif, 1.5% for rabi food and oilseed crops, and 5% for commercial and horticultural crops, so it is not uniform; statement 1 is wrong. The scheme covers post-harvest losses for up to 14 days from cyclones, cyclonic rain and unseasonal rain (2).
The rest of the premium is shared by the Centre and States, and enrolment became voluntary in 2020. Technology such as remote sensing and drones is used to assess crop loss. Notice how insurance shields farmers from climate risk.
Answer as per the official UPSC answer key.
Which of the following statements is/are correct?
Proper design and effective implementation of UN-REDD+ Programme can significantly contribute to
- 1. protection of biodiversity
- 2. resilience of forest ecosystems
- 3. poverty reduction
Select the correct answer using the code given below.
Answer (d) & explanation
All three are correct (d). REDD+ (Reducing Emissions from Deforestation and forest Degradation, plus conservation, sustainable management and enhancing carbon stocks) pays developing countries for keeping forests standing. UN-REDD, started in 2008, is run jointly by the FAO, UNDP and UNEP. If it is well designed, it brings co-benefits: standing forests protect biodiversity (1), healthy and connected forests are more resilient to climate stress (2), and payments that reach forest communities help reduce poverty (3).
The word "proper design" in the question is the clue. Badly designed REDD+ can push out tribal people. That is why safeguards on indigenous rights matter, and in India they link with the Forest Rights Act, 2006.
Answer as per the official UPSC answer key.
In the cities of our country, which among the following atmospheric gases are normally considered in calculating the value of Air Quality Index?
- 1. Carbon dioxide
- 2. Carbon monoxide
- 3. Nitrogen dioxide
- 4. Sulfur dioxide
- 5. Methane
Select the correct answer using the code given below.
Answer (b) & explanation
Carbon monoxide, nitrogen dioxide and sulphur dioxide are counted (b). India's National Air Quality Index, launched in 2014 and run by the CPCB, uses eight pollutants: PM₁₀, PM₂.₅, NO₂ (3), SO₂ (4), CO (2), O₃, NH₃ and lead. It has six bands from "Good" to "Severe", and the worst pollutant sets the overall value. CO₂ (1) and methane (5) are greenhouse gases that warm the planet, but they are not local health pollutants in the AQI sense. So any option with 1 or 5 is wrong.
Notice the related schemes: the National Clean Air Programme (2019) targets 40% lower particulate levels in 130 cities by 2025–26, and GRAP steps up curbs in Delhi-NCR as the AQI worsens.
CO2 and methane warm the planet, but the AQI measures harm from breathing, so they are left out.
UPSC repeats traps like this year after year. The PYQ Book gathers every trap in one place, so you see them coming. Try the free sample
Answer as per the official UPSC answer key.
(Same information as the question above.)
Who is the artist ?
Answer (c) & explanation
R is the artist (c). Step 1: P and S are students, so the three jobs belong to Q, R and T. Step 2: Q is neither the doctor nor the artist, so Q is the lawyer. Step 3: R is not the doctor. The only job left for R is artist, and T is the doctor. So option (c) is right. Option (a) P is a student and has no job. Option (b) Q is the lawyer. Option (d) T is the doctor.
Tip: linked questions share one grid. Solve the grid fully once, then answer every question from it. This saves time and avoids answering the same puzzle in different ways.
Answer as per the official UPSC answer key.
Read the passage
About 15 per cent of global greenhouse gas emissions come from agricultural practices. This includes nitrous oxide from fertilizers; methane from livestock, rice production, and manure storage; and carbon dioxide (CO₂) from burning biomass, but this excludes CO₂ emissions from soil management practices, savannah burning and deforestation. Forestry, land use, and land-use change account for another 17 per cent of greenhouse gas emissions each year, three quarters of which come from tropical deforestation. The remainder is largely from draining and burning tropical peatland. About the same amount of carbon is stored in the world’s peatlands as is stored in the Amazon rainforest.
Which among the following is the most logical and rational inference that can be made from the above passage ?
Answer (b) & explanation
We must change our land use practices to fight climate change (b). Step 1: the passage says agriculture causes about 15% and land use change about 17% of greenhouse gas emissions. Together that is about a third. Step 2: so changing how we use land is a must, which is option (b). Step 3: option (a) wants organic farming "immediately… all over the world", which is far too extreme. Option (c), that there are no technical fixes, is not discussed. Option (d), that tropics are the main carbon store, is not stated.
Tip: agriculture and land use are big emission sources because of fertilisers, livestock and forest clearing. That is why climate plans stress forests and farming.
Answer as per the official UPSC answer key.
A person allows a 10% discount for cash payment from the marked price of a toy and still he makes a 10% gain. What is the cost price of the toy which is marked Rs. 770?
Answer (c) & explanation
The cost price is Rs 630 (c). Step 1: the marked price is Rs 770. A 10% discount gives a selling price of 90% of 770 = Rs 693. Step 2: he still makes a 10% profit, so 693 is 110% of the cost price. Step 3: cost price = 693 ÷ 1.1 = Rs 630. Check: 630 + 10% = 693. Option (a), Rs 610, and options (b) and (d) do not fit. A common mistake is to think a 10% discount and a 10% gain cancel out, giving 770.
Tip: discount is always on the marked price, and profit is always on the cost price. Keep the two bases separate.
Answer as per the official UPSC answer key.
‘Mission Indradhanush’ launched by the Government of India pertains to
Answer (a) & explanation
Mission Indradhanush (December 2014) is about the immunisation of children and pregnant women (a). It targets children under two and pregnant women who were missed or left partly vaccinated under routine immunisation. It has nothing to do with smart cities (b), which come under the Smart Cities Mission, space research for Earth-like planets (c), or the education policy (d).
The seven rainbow colours first stood for seven vaccine-preventable diseases; more vaccines were added later. Intensified Mission Indradhanush pushed coverage further, and the U-WIN portal now tracks doses digitally. Notice how it supports the Universal Immunisation Programme, one of the largest in the world.
Answer as per the official UPSC answer key.
What is/are common to the two historical places known as Ajanta and Mahabalipuram?
- 1. Both were built in the same period.
- 2. Both belong to the same religious denomination.
- 3. Both have rock-cut monuments.
Select the correct answer using the code given below.
Answer (b) & explanation
Only statement 3 is correct (b). The Ajanta caves in Maharashtra are Buddhist. They were cut in two phases: about the 2nd–1st century BCE under the Satavahanas and the 5th century CE under the Vakatakas. Mahabalipuram's rathas, mandapas and reliefs are Hindu and were made by the Pallavas in the 7th–8th centuries, under rulers like Narasimhavarman I. So statement 1 (same period) and statement 2 (same religion) are wrong. Only the rock-cut technique is common to both.
Both are UNESCO World Heritage Sites, and Ajanta is famous above all for its murals. Notice that Mahabalipuram also has the structural Shore Temple, built under Rajasimha. It marks the move from rock-cut to stone-built temples in the south.
Answer as per the official UPSC answer key.
Consider the following statements :
- 1. The Sustainable Development Goals were first proposed in 1972 by a global think tank called the ‘Club of Rome’.
- 2. The Sustainable Development Goals have to be achieved by 2030.
Which of the statements given above is/are correct?
Answer (b) & explanation
Only statement 2 is correct (b). The SDGs were proposed at Rio+20 (2012), with Colombia and Guatemala pushing the idea. The UN adopted them in September 2015 as Agenda 2030: 17 goals and 169 targets to be met by 2030 (2). They replaced the eight MDGs (2000–2015). Statement 1 is wrong because the Club of Rome's 1972 report The Limits to Growth warned about resource limits but never proposed the SDGs.
In India, NITI Aayog tracks progress through its SDG India Index, and Kerala and Uttarakhand usually rank at the top. Notice the related term sustainable development, made popular by the Brundtland Report, Our Common Future (1987): meeting today's needs without harming future generations.
Answer as per the official UPSC answer key.
Four friends A, B, C and D need to cross a bridge. A maximum of two persons can cross it at a time. It is night and they just have one lamp. Persons that cross the bridge must carry the lamp to find the way. A pair must walk together at the speed of slower person. After crossing the bridge, the person having faster speed in the pair will return with the lamp each time to accompany another person in the group. Finally, the lamp has to be returned at the original place and the person who returns the lamp has to cross the bridge again without lamp. To cross the bridge, the time taken by them is as follows : A: 1 minute, B: 2 minutes, C: 7 minutes and D: 10 minutes. What is the total minimum time required by all the friends to cross the bridge ?
Answer (a) & explanation
The minimum time is 23 minutes (a). Step 1: the rule says the faster person of each pair brings the lamp back. So A, the fastest (1 minute), should walk with everyone. Step 2: A + D cross (10), A returns (1), A + C cross (7), A returns (1), A + B cross (2). That is 21 minutes, and all four are across. Step 3: the puzzle adds that the lamp must be returned to the start, and the person who returns it must cross again without the lamp. A returns (1) and crosses back (1): 21 + 2 = 23 minutes. Option (c), 21, forgets this last rule. Options (b) and (d) do not follow the rules.
Tip: read every rule to the end; the last line often changes the answer.
the usual 17-minute trick (C and D crossing together) is not allowed here, because the faster person must return each time.
Answer as per the official UPSC answer key.
A cube has all its faces painted with different colours. It is cut into smaller cubes of equal sizes such that the side of the small cube is one-fourth the big cube. The number of small cubes with only one of the sides painted is :
Answer (b) & explanation
24 small cubes have only one face painted (b). Step 1: each side is cut into 4, so the big cube becomes 4 × 4 × 4 = 64 small cubes. Step 2: on each face there are 4 × 4 = 16 small cubes. The ones on the edges of that face also touch another face. Only the inner 2 × 2 = 4 have just one painted side. Step 3: a cube has 6 faces, so 6 × 4 = 24. Option (a), 32, does not fit. Option (d), 8, is the number of corner cubes, which have three painted faces.
Tip: for a cube cut n × n × n, one-face cubes = 6 × (n − 2)². Corner cubes are always 8.
Answer as per the official UPSC answer key.
In the context of which of the following do you sometimes find the terms 'amber box, blue box and green box' in the news?
Answer (a) & explanation
The terms belong to WTO affairs (a). The Agreement on Agriculture sorts farm subsidies into boxes. Amber box subsidies, such as price support, distort trade and are capped. Blue box subsidies are tied to production limits, and green box subsidies, such as research and environmental programmes, cause minimal distortion; neither is capped. SAARC (b), the UNFCCC (c) and India–EU FTA talks (d) do not use these terms.
Developing countries also have a de minimis allowance of 10% of production value. Notice how India's MSP procurement is debated within these rules, linked to the Peace Clause.
Answer as per the official UPSC answer key.
What is/are the purpose/purposes of the 'Marginal Cost of Funds based Lending Rate (MCLR)' announced by RBI?
- 1. These guidelines help improve the transparency in the methodology followed by banks for determining the interest rates on advances.
- 2. These guidelines help ensure availability of bank credit at interest rates which are fair to the borrowers as well as the banks.
Select the correct answer using the code given below.
Answer (c) & explanation
Both statements are correct (c). The RBI introduced MCLR in April 2016 to make banks' loan-pricing method more transparent (1) and to ensure credit at rates fair to both borrowers and banks (2). Banks set lending rates from their marginal, or latest, cost of funds using a fixed formula, so policy rate cuts reach borrowers faster than under the old base rate.
MCLR replaced the base rate system (2010). Because transmission was still slow, from October 2019 new floating-rate retail and MSME loans were linked to an external benchmark such as the repo rate. Notice how each change aims at faster monetary transmission.
Answer as per the official UPSC answer key.
Regarding 'Atal Pension Yojana', which of the following statements is/are correct?
- 1. It is a minimum guaranteed pension scheme mainly targeted at unorganized sector workers.
- 2. Only one member of a family can join the scheme.
- 3. Same amount of pension is guaranteed for the spouse for life after subscriber's death.
Select the correct answer using the code given below.
Answer (c) & explanation
Statements 1 and 3 are correct (c). Atal Pension Yojana (2015), run by PFRDA under the NPS setup, guarantees a monthly pension of ₹1,000 to ₹5,000 from age 60. It is aimed mainly at unorganised sector workers who join between 18 and 40 (1). After the subscriber dies, the spouse gets the same pension for life (3), and then the nominee receives the built-up corpus. Statement 2 is wrong because there is no one-per-family limit. Any eligible citizen with a savings bank account can join.
Since October 2022, income-tax payers cannot join. Notice how it differs from PM-SYM, a 50:50 matched-contribution scheme that pays a fixed ₹3,000 to unorganised workers. APY is now one of India's largest micro-pension schemes.
"only one member of a family". That limit belongs to no pension scheme; do not mix it up with household-based schemes.
Answer as per the official UPSC answer key.
Read the passage
In general, religious traditions stress our duty to god, or to some universal ethical principle. Our duties to one another derive from these. The religious concept of rights is primarily derived from our relationship to this divinity or principle and the implication it has on our other relationships. This correspondence between rights and duties is critical to any further understanding of justice. But, for justice to be practiced; virtue, rights and duties cannot remain formal abstractions. They must be grounded in a community (common unity) bound together by a sense of common union (communion). Even as a personal virtue, this solidarity is essential to the practice and understanding of justice.
Which one of the following is the crux of this passage ?
Answer (c) & explanation
The crux is that a balance between rights and duties is crucial to justice (c). Step 1: the key line is: "This correspondence between rights and duties is critical to any further understanding of justice." The whole passage builds towards this point. Step 2: option (a), that duties come from religious traditions, is an opening detail, not the main point. Option (d), that rights come from our relationship to god, is also a detail. Step 3: option (b), calling a relationship to the divine a great virtue, is a value judgement the passage never makes.
Tip: the crux is the idea the other sentences support. Supporting details from the start of a passage are common trap options.
Answer as per the official UPSC answer key.
A daily train is to be introduced between station A and station B starting from each end at 6 AM and the journey is to be completed in 42 hours. What is the number of trains needed in order to maintain the shuttle service ?
Answer (c) & explanation
1. Day 1, 6 AM: one train leaves A and one leaves B. That is 2 trains.
2. 42 hours = 1 day and 18 hours, so these trains arrive at midnight at the end of Day 2. On Day 2 at 6 AM they are still running, so 2 more trains are needed.
3. Day 3, 6 AM: the Day 1 trains have arrived and can go back. No new train is needed after this.
4. Total = 4 trains.
Answer as per the official UPSC answer key.
Read the passage
Historically, the biggest challenge to world agriculture has been to achieve a balance between demand for and supply of food. At the level of individual countries, the demand-supply balance can be a critical policy issue for a closed economy, especially if it is a populous economy and its domestic agriculture is not growing sufficiently enough to ensure food supplies, on an enduring basis; it is not so much and not always, of a constraint for an open, and growing economy, which has adequate exchange surpluses to buy food abroad. For the world as a whole, supply-demand balance is always an inescapable prerequisite for warding off hunger and starvation. However, global availability of adequate supply does not necessarily mean that food would automatically move from countries of surplus to countries of deficit if the latter lack in purchasing power. The uneven distribution of hunger, starvation, under- or malnourishment, etc., at the world-level, thus owes itself to the presence of empty-pocket hungry mouths, overwhelmingly confined to the underdeveloped economies. Inasmuch as ‘a two-square meal’ is of elemental significance to basic human existence, the issue of worldwide supply of food has been gaining significance, in recent times; both because the quantum and the composition of demand has been undergoing big changes, and because, in recent years, the capabilities of individual countries to generate uninterrupted chain of food supplies have come under strain. Food production, marketing and prices, especially price-affordability by the poor in the developing world, have become global issues that need global thinking and global solutions.
According to the above passage, which of the following helps/help in reducing hunger and starvation in the developing economies ?
- 1. Balancing demand and supply of food
- 2. Increasing imports of food
- 3. Increasing purchasing power of the poor
- 4. Changing the food consumption patterns and practices
Select the correct answer using the code given below :
Answer (c) & explanation
Statements 1 and 3 help reduce hunger (c). Step 1: the passage calls the balance of food demand and supply an "inescapable prerequisite". So statement 1 helps. Step 2: it says hunger comes from "empty-pocket hungry mouths". People are hungry because they cannot buy food. So raising the poor's purchasing power (3) helps. Step 3: increasing imports (2) needs money, so imports alone do not reach the poor. Changing food habits (4) is not suggested. So options (a), (b) and (d) fail.
Tip: this echoes Amartya Sen's idea of entitlement. Famines often happen not from a lack of food, but because the poor lack the income to buy it.
Answer as per the official UPSC answer key.
In which of the following regions of India are you most likely to come across the ‘Great Indian Hornbill’ in its natural habitat?
Answer (d) & explanation
The Great Indian Hornbill needs tall evergreen and moist deciduous forest with big fruiting trees and nesting holes. In India it lives in the Western Ghats (d) and in the forests of the North-East and Himalayan foothills. The sand deserts (a), high Himalayas (b) and salt marshes of Gujarat (c) lack such forest.
It is the state bird of Kerala and Arunachal Pradesh. Hornbills are called "farmers of the forest" because they spread seeds of many trees. The Hornbill Festival of Nagaland is named after it. Notice how one bird's survival depends on old, tall trees.
Answer as per the official UPSC answer key.
What is ‘Greenhouse Gas Protocol’?
Answer (a) & explanation
The GHG Protocol is an accounting tool (a). It was built by the World Resources Institute (WRI) and the World Business Council for Sustainable Development (WBCSD). It is the most widely used standard for measuring and managing emissions. It sorts emissions into Scope 1 (direct), Scope 2 (purchased electricity) and Scope 3 (the value chain). It is not a UN financial incentive (b); that describes REDD+ or climate funds. It is not a treaty with a 2022 target (c), and it is not a World Bank REDD+ initiative (d), such as the Forest Carbon Partnership Facility.
Notice how this matters today. SEBI's BRSR reporting for listed companies and India's Carbon Credit Trading Scheme both rely on this kind of emissions accounting.
Answer as per the official UPSC answer key.