UPSC Prelims PYQs with explanations
Real questions from official papers, mapped to syllabus topics. Attempt each one; the answer and the reason appear instantly.
The provisions in Fifth Schedule and Sixth Schedule in the Constitution of India are made in order to
Answer (a) & explanation
Both schedules exist to protect the interests of Scheduled Tribes (a). The Fifth Schedule governs Scheduled Areas and tribes in most States, with Tribes Advisory Councils and special powers for the Governor. The Sixth Schedule sets up autonomous district councils in tribal areas of Assam, Meghalaya, Tripura and Mizoram. They do not fix State boundaries (b) or deal with border States (d). Panchayats (c) are in the Eleventh Schedule.
PESA (1996) extends panchayat self-rule to Fifth Schedule areas. Notice how the Constitution balances integration with protection of tribal identity.
Answer as per the official UPSC answer key.
With reference to bio-toilets used by the Indian Railways, consider the following statements :
- 1. The decomposition of human waste in the bio-toilets is initiated by a fungal inoculum.
- 2. Ammonia and water vapour are the only end products in this decomposition which are released into the atmosphere.
Select the correct answer using the code given below.
Answer (d) & explanation
Neither statement is correct (d). The bio-toilets on Indian Railways use a DRDO bio-digester with an anaerobic bacterial inoculum, not a fungal one, so statement 1 is wrong. The technology was first developed for soldiers' waste in the cold heights of Siachen. Statement 2 is wrong because the end products are mainly methane, carbon dioxide and water, not just ammonia and water vapour.
Railways fitted bio-toilets in all coaches to end open discharge of waste onto tracks, improving hygiene and reducing rail corrosion. Notice how defence research found a civilian use supporting Swachh Bharat.
Answer as per the official UPSC answer key.
Read the passage
Set against a rural backdrop, ‘Stench of kerosene’ is the story of a couple, Guleri and Manak, who have been happily married for several years but do not have a child. Manak’s mother is desperate to have a grandchild to carry on the family name. Hence, she gets Manak remarried in Guleri’s absence. Manak, who acts as a reluctant but passive spectator, is meanwhile, informed by a friend that Guleri, on hearing about her husband’s second marriage, poured kerosene on her clothes and set fire to them. Manak is heartbroken and begins to live as if he were a dead man. When his second wife delivers a son, Manak stares at the child for a long time and blurts out, “Take him away! He stinks of kerosene.”
This is a sensitive issue-based story which tries to sensitise the readers about
Answer (d) & explanation
The story sensitises readers to the influence of a patriarchal mindset (d). Step 1: find what drives the tragedy. Manak's mother is desperate for a grandchild "to carry on the family name", so she gets him remarried. Wanting a male heir to continue the family name is a patriarchal idea. Guleri's death follows. Step 2: test the others. Option (a) is wrong: Manak is a "reluctant but passive spectator", not a man seeking another woman, so infidelity misreads him. Option (b) is too general. Option (c) is wrong: legal safeguards are not discussed.
Tip: for theme questions, find the root cause of events in the story, not just the events themselves. Here the root cause is the pressure for an heir.
Answer as per the official UPSC answer key.
Each of the six different faces of a cube has been coated with a different colour i.e., V, I, B, G, Y and O. Following information is given :
- 1. Colours Y, O and B are on adjacent faces.
- 2. Colours I, G and Y are on adjacent faces.
- 3. Colours B, G and Y are on adjacent faces.
- 4. Colours O, V and B are on adjacent faces.
Which is the colour of the face opposite to the face coloured with O ?
Answer (c) & explanation
G is opposite O (c). Step 1: a face cannot be adjacent to its opposite face. Find each colour's neighbours. Y appears with O, B, I and G. That is four neighbours, so Y is opposite the only one left, V. Step 2: B appears with Y, O, G and V. So B is opposite the remaining one, I. Step 3: the only pair left is O and G. So G is opposite O. Options (a), (b) and (d) are adjacent to O or already paired.
Tip: on a cube, each face touches four others and is opposite one. List each colour's neighbours; once a colour has four, its opposite is the missing one.
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.
Which one of the following regions of India has a combination of mangrove forest, evergreen forest and deciduous forest?
Answer (d) & explanation
The Andaman and Nicobar Islands combine mangroves along creeks and coasts, tropical evergreen forest in the wet interior and moist deciduous forest on drier slopes (d). North Coastal Andhra (a) has mainly dry deciduous forest. South-West Bengal (b), with the Sundarbans, is mostly mangrove, and Southern Saurashtra (c) is dry, with thorn and dry deciduous forest.
The islands get heavy rain from both monsoons and lie near the equator, which explains this rich mix. Notice how island ecosystems are rich but fragile, as debates over the Great Nicobar project show.
Answer as per the official UPSC answer key.
Tides occur in the oceans and seas due to which among the following?
- 1. Gravitational force of the Sun
- 2. Gravitational force of the Moon
- 3. Centrifugal force of the Earth
Select the correct answer using the code given below.
Answer (d) & explanation
All three contribute (d). Tides come from the Moon's gravitational pull (2), which is the strongest effect; the Sun's pull (1), which is weaker but still important; and the centrifugal force of the Earth–Moon system turning around a common centre (3). The pull creates a bulge facing the Moon, and the centrifugal effect creates one on the opposite side.
When Sun, Moon and Earth line up at new and full moon, the pulls add up to give spring tides. At right angles, during quarter moons, they partly cancel to give neap tides. Notice how the Gulf of Khambhat's high tides make it a site for tidal energy.
Answer as per the official UPSC answer key.
Read the passage
Human history abounds in claims and theories confining the right of governing to a few select citizens. Exclusion of the many is justified on the ground that human beings may be rightfully segregated for the good of society and viability of the political process.
Which one of the following statements is least essential as a part of the argument in the above passage ?
Answer (a) & explanation
Statement (a) is least essential to the argument (a). Step 1: find the argument. The passage says some theories give the right to govern to "a few select citizens", excluding the many "for the good of society and viability of the political process". Step 2: check what this argument needs. It needs humans to be unequal, some "super" and some "sub" (b). It needs exclusion to help the system work (c). It needs the idea that people have different capacities to govern (d). Step 3: option (a), man seeking control over external things, plays no part in the argument. So it is least essential.
Tip: for "least essential" questions, ask of each option: "If I remove this, does the argument collapse?" The one whose removal changes nothing is the answer.
Answer as per the official UPSC answer key.
Shahid and Rohit start from the same point in opposite directions. After each 1 km, Shahid always turns left and Rohit always turns right. Which of the following statements is correct ?
Answer (b) & explanation
They meet after each has travelled 3 km (b). Step 1: Shahid walks north and Rohit south, in opposite directions. After 1 km, Shahid turns left (west) and Rohit turns right (also west, since he faces south). Step 2: after 2 km each, both have gone 1 km west. They are still 2 km apart (one north, one south of the start). So (a), saying 4 km, is wrong. Step 3: now Shahid turns left again, to south, and Rohit turns right again, to north. They walk toward each other and meet after 1 km more. Each has travelled 3 km. Options (c) and (d) are wrong.
Tip: draw the paths on paper. "Left" and "right" depend on which way a person is facing.
Answer as per the official UPSC answer key.
Read the passage
Climate change is a complex policy issue with major implications in terms of finance. All actions to address climate change ultimately involve costs. Funding is vital for countries like India to design and implement adaptation and mitigation plans and projects. Lack of funding is a large impediment to implementing adaptation plans. The scale and magnitude of the financial support required by developing countries to enhance their domestic mitigation and adaptation actions are a matter of intense debate in the multilateral negotiations under the United Nations Framework Convention on Climate Change (UNFCCC). The Convention squarely puts the responsibility for provision of financial support on the developed countries, taking into account their contribution to the stock of greenhouse gases (GHGs) in the atmosphere. Given the magnitude of the task and the funds required, domestic finances are likely to fall short of the current and projected needs of the developing countries. Global funding through the multilateral mechanism of the Convention will enhance their domestic capacity to finance the mitigation efforts.
In this passage, the Convention puts the responsibility for the provision of financial support on the developed countries because of
- 1. their higher level of per capita incomes.
- 2. their large quantum of GDP.
- 3. their large contribution to the stock of GHGs in the atmosphere.
Select the correct answer using the code given below :
Answer (c) & explanation
Their contribution to greenhouse gases is the reason (c). Step 1: find the line. The Convention puts the responsibility on developed countries, "taking into account their contribution to the stock of greenhouse gases (GHGs) in the atmosphere". That is item 3. Step 2: test items 1 and 2. Higher per capita income and large GDP are not given as reasons, even though they are true facts about rich countries. So options (a), (b) and (d) fail.
Tip: this is the idea of historical responsibility: those who polluted most in the past should pay most now. It underlies the UNFCCC principle of Common But Differentiated Responsibilities (CBDR). In "according to the passage" questions, accept only the reason the text actually gives.
Answer as per the official UPSC answer key.
Among the following, which were frequently mentioned in the news for the outbreak of Ebola virus recently?
Answer (b) & explanation
The 2014–16 West African Ebola epidemic, the largest ever with over 11,000 deaths, centred on Guinea, Sierra Leone and Liberia (b). WHO declared it a Public Health Emergency of International Concern in August 2014. The other groups, Syria–Jordan (a), Philippines–Papua New Guinea (c) and Jamaica–Haiti–Surinam (d), were not Ebola hotspots.
The virus is named after the Ebola river in the DR Congo, where it was first identified in 1976. It spreads through direct contact with body fluids. Notice how such outbreaks shaped later global health responses, including WHO's handling of Zika and COVID-19.
Answer as per the official UPSC answer key.
Which of the following statements regarding ‘Green Climate Fund’ is/are correct?
- 1. It is intended to assist the developing countries in adaptation and mitigation practices to counter climate change.
- 2. It is founded under the aegis of UNEP, OECD, Asian Development Bank and World Bank.
Select the correct answer using the code given below.
Answer (a) & explanation
Only statement 1 is correct (a). The Green Climate Fund was set up at Cancún (COP16, 2010) under the UNFCCC financial mechanism to help developing countries with adaptation and mitigation. Statement 2 is wrong: UNEP, the OECD, ADB and the World Bank did not found it, though the World Bank acted as its interim trustee.
Its headquarters is in Songdo, South Korea, and it aims to split funding evenly between mitigation and adaptation. Notice how climate finance remains a key North–South issue, seen in the new finance goal agreed at COP29 in Baku in 2024.
Answer as per the official UPSC answer key.
With reference to Indian economy, consider the following statements :
- 1. The rate of growth of Real Gross Domestic Product has steadily increased in the last decade.
- 2. The Gross Domestic Product at market prices (in rupees) has steadily increased in the last decade.
Which of the statements given above is/are correct?
Answer (b) & explanation
Only statement 2 is correct (b). The real GDP growth rate rose and fell between 2005 and 2015, dipping in 2008-09 after the global financial crisis and again in 2012-13, so it did not rise steadily. Nominal GDP at market prices in rupees rose every year because of both real growth and inflation.
The key idea is that a level can rise steadily even when its growth rate does not. Real GDP removes the effect of price changes, while nominal GDP does not. Notice how the GDP deflator links the two, and how this distinction appears in many economics questions.
Answer as per the official UPSC answer key.
Consider the following matrix :
| 3 | 8 | 10 | 2 | ? | 1 |
|---|---|---|---|---|---|
| 6 | 56 | 90 | 2 | 20 | 0 |
What is the missing number at '?' in the matrix ?
Answer (a) & explanation
The missing number is 5 (a). Step 1: look for a rule linking the top and bottom numbers. 3 → 6: 3 × 2 = 6. 8 → 56: 8 × 7 = 56. 10 → 90: 10 × 9 = 90. 1 → 0: 1 × 0 = 0. So bottom = top × (top − 1). Step 2: for the missing top number, the bottom is 20. Which number times one less than itself gives 20? 5 × 4 = 20. So the answer is 5. Options (b), (c) and (d) do not fit: 0 × (−1) = 0, 7 × 6 = 42, 3 × 2 = 6.
Tip: when numbers look like 6, 56, 90, think of products of neighbours: 2 × 3, 7 × 8, 9 × 10. Spotting such pairs is a common CSAT shortcut.
Answer as per the official UPSC answer key.
Read the passage
We generally talk about democracy but when it comes to any particular thing, we prefer a belonging to our caste or community or religion. So long as we have this kind of temptation, our democracy will remain a phoney kind of democracy. We must be in a position to respect a man as a man and to extend opportunities for development to those who deserve them and not to those who happen to belong to our community or race. This fact of favouritism has been responsible for much discontent and ill-will in our country.
Which one of the following statements best sums up the above passage ?
Answer (b) & explanation
True democracy needs equal opportunities for all (b). Step 1: find the main point. The author says we prefer people of our own caste, community or religion. This makes our democracy "phoney". We must "respect a man as a man" and give opportunities to those who deserve them. That is equal opportunity. Step 2: test the others. Option (a) is wrong: diversity is the background, not the message. Option (c) is wrong: "none of us" is too strong. Option (d) is wrong: "never" is too pessimistic; the author suggests a fix.
Tip: when a passage criticises a problem and then says "we must...", the "must" line is usually the summary.
Answer as per the official UPSC answer key.
In a plane, line X is perpendicular to line Y and parallel to line Z; line U is perpendicular to both lines V and W; line X is perpendicular to line V. Which one of the following statements is correct?
Answer (d) & explanation
Y, V and W are parallel (d). Step 1: use one rule: in a flat plane, two lines perpendicular to the same line are parallel. Step 2: Y and V are both perpendicular to X, so Y ∥ V. Step 3: U is perpendicular to V, and X is also perpendicular to V, so U ∥ X. Step 4: W is perpendicular to U. U is parallel to X, so W is perpendicular to X too. Like Y and V, W is perpendicular to X, so W ∥ V ∥ Y. Options (a), (b) and (c) mix up parallel and perpendicular lines.
Tip: sort the lines into two families: lines like X (here X, Z, U) and lines at right angles to them (Y, V, W). Lines within a family are parallel.
Answer as per the official UPSC answer key.
The Government of India Act of 1919 clearly defined
Answer (b) & explanation
The Government of India Act, 1919 clearly defined the jurisdiction of the central and provincial governments (b). Its Devolution Rules split subjects into central and provincial lists, loosening central control over the provinces. Provincial subjects were further split into reserved and transferred under dyarchy. It did not set out a separation of powers between judiciary and legislature (a), and the powers of the Secretary of State and Viceroy (c) were not its defining feature, so (d) also fails.
The Act followed the Montagu–Chelmsford reforms. Notice how it also brought bicameralism at the Centre.
Answer as per the official UPSC answer key.
With reference to the Union Government, consider the following statements :
- 1. The Department of Revenue is responsible for the preparation of Union Budget that is presented to the Parliament.
- 2. No amount can be withdrawn from the Consolidated Fund of India without the authorization from the Parliament of India.
- 3. All the disbursements made from Public Account also need the authorization from the Parliament of India.
Which of the statements given above is/are correct?
Answer (c) & explanation
Only statement 2 is correct (c). The Union Budget is prepared by the Budget Division of the Department of Economic Affairs, not the Department of Revenue, so statement 1 is wrong. No money can be withdrawn from the Consolidated Fund without a law passed by Parliament (Articles 114 and 266(3)). Statement 3 is wrong: the Public Account holds money such as provident funds and deposits that belong to others, and payments from it need no vote.
The third fund, the Contingency Fund (Article 267), is held by the President for emergencies. Notice how parliamentary control over money ensures accountability.
the Department of Revenue sounds like the Budget office. It handles taxes, not the Budget document.
Answer as per the official UPSC answer key.
The problem of international liquidity is related to the non-availability of
Answer (c) & explanation
International liquidity means the stock of assets accepted for settling international payments: US dollars and other hard currencies, plus gold, SDRs and IMF reserve positions. So the problem relates to their non-availability (c). A shortage of goods and services (a) or an exportable surplus (d) affects trade but is not liquidity itself. Gold and silver (b) are only part of the story; silver plays no role today.
India faced a severe liquidity crisis in 1991, when reserves fell to about two weeks of imports and gold was pledged. Notice how this led to the economic reforms and why forex reserves matter.
Answer as per the official UPSC answer key.
Read the passage
The ultimate aim of government is not to rule or control by fear, nor to demand obedience, but conversely, to free every man from fear, that he may live in all possible security. In other words, to strengthen his natural right to exist and work without injury to himself or others. The object of government is not to change men from rational beings into beasts or puppets. It should enable them to develop their minds and bodies in security, and to employ their reason unshackled.
Which among the following is the most logical and rational inference that can be made from the above passage ?
Answer (a) & explanation
Government's true aim is to secure citizens' social and political freedom (a). Step 1: find the aim. Government should "free every man from fear", let him live "in all possible security", and let him "employ his reason unshackled". This is about freedom with security. Step 2: test the others. Options (b), (c) and (d) all use "absolute". The passage limits freedom: man should act "without injury to himself or others". So absolute security or absolute liberty goes beyond it. Option (c) also misses the role of security.
Tip: watch for extreme words like "absolute", "all" and "only". If the passage puts limits on an idea, an option that removes those limits is wrong.
Answer as per the official UPSC answer key.