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 countries :
- 1. Bulgaria
- 2. Czech Republic
- 3. Hungary
- 4. Latvia
- 5. Lithuania
- 6. Romania
How many of the above-mentioned countries share a land border with Ukraine?
Answer (a) & explanation
Two of the countries border Ukraine (a). Ukraine shares land borders with Russia, Belarus, Poland, Slovakia, Hungary, Romania and Moldova. From this list only Hungary (item 3) and Romania (item 6) qualify. Item 1 is wrong: Bulgaria lies across the Black Sea, with Romania in between. Item 2 is wrong: the Czech Republic is cut off by Slovakia and Poland. Items 4 and 5 are wrong: Latvia and Lithuania are Baltic states, separated from Ukraine by Belarus.
Notice the war's geography: Odesa port, the Danube grain route through Romania, and the Black Sea grain corridor. Moldova's breakaway Transnistria region, with Russian troops, borders Ukraine too.
Slovakia is a neighbour of Ukraine, and the Czech Republic is listed in its place.
Answer as per the official UPSC answer key.
Consider the following statements :
Statement-I : Israel has established diplomatic relations with some Arab States.
Statement-II : The ‘Arab Peace Initiative’ mediated by Saudi Arabia was signed by Israel and Arab League.
Which one of the following is correct in respect of the above statements?
Answer (c) & explanation
Statement I is correct but Statement II is wrong (c). Statement I is right: Israel has diplomatic ties with Egypt (1979) and Jordan (1994), and with the UAE, Bahrain, Morocco and Sudan under the Abraham Accords (2020), brokered by the USA. Statement II is wrong: the Arab Peace Initiative (2002) was a Saudi proposal endorsed by the Arab League. It offered full ties with Israel in return for withdrawal to the 1967 borders and a Palestinian state. Israel never signed it.
Notice how the Gaza war from October 2023 froze talks on Saudi–Israel normalisation. India's link: the I2U2 group (India, Israel, UAE, USA) and the IMEC corridor depend on such ties.
Answer as per the official UPSC answer key.
Read the passage
Elephants are landscape architects, creating clearings in the forest, preventing overgrowth of certain plant species and allowing space for the regeneration of others, which in turn provide sustenance to other herbivorous animals. Elephants eat plants, fruits and seeds, propagating the seeds when they defecate in other places as they travel. Elephant dung provides nourishment to plants and animals and acts as a breeding ground for insects. In times of drought, they access water by digging holes which benefits other wildlife.
Which one of the following statements best reflects the most logical and rational inference that can be drawn from the passage ?
Answer (b) & explanation
The best inference is that elephants are a keystone species that benefit biodiversity (b). Step 1: the passage says elephants make clearings, spread seeds through dung, feed insects and plants with dung, and dig waterholes in drought. Step 2: all these help many other species. A species whose role supports so many others is a keystone species. That is (b). Step 3: option (c) says biodiversity cannot survive without them, which is too absolute. Option (d) gives elephants a purpose, as if they plan the forest. Option (a) talks of home range, which is not discussed.
Tip: a keystone species has a large effect on its ecosystem relative to its numbers. India declared the elephant its National Heritage Animal in 2010.
Answer as per the official UPSC answer key.
What is the middle term of the sequence
Z, Z, Y, Y, Y, X, X, X, X, W, W, W, W, W, …, A ?
Answer (b) & explanation
The middle term is I (b). Step 1: Z appears 2 times, Y 3 times, X 4 times, and so on. The kth letter from Z appears k + 1 times, so A appears 27 times. Step 2: total terms = 2 + 3 + ... + 27 = 377. The middle term is the 189th. Step 3: the first m letters fill m(m + 3)/2 places. For m = 18 this is exactly 189. The 18th letter counting back from Z is I. Options (a) H, (c) J and (d) M are off.
Tip: counting back from Z, letter number k is the letter at position 27 − k. Here 27 − 18 = 9, which is I.
Answer as per the official UPSC answer key.
About three-fourths of world’s cobalt, a metal required for the manufacture of batteries for electric motor vehicles, is produced by
Answer (c) & explanation
The DR Congo produces about three-fourths of the world's cobalt (c). The Democratic Republic of the Congo mines about 70–75% of the world's cobalt, mainly from the Katanga copper-cobalt belt in its south. Much of this cobalt is refined in China, which controls most of the supply chain. Cobalt is used in lithium-ion batteries for phones and electric vehicles. Argentina (a) is known for lithium, as part of the lithium triangle with Chile and Bolivia. Botswana (b) is famous for diamonds. Kazakhstan (d) is the top producer of uranium.
Notice the ethics issue: child labour in small artisanal mines has pushed EV makers to trace their supply. India's KABIL joint venture seeks such critical minerals abroad.
Answer as per the official UPSC answer key.
With reference to 'Scheduled Areas' in India, consider the following statements :
- 1. Within a State, the notification of an area as Scheduled Area takes place through an Order of the President.
- 2. The largest administrative unit forming the Scheduled Area is the District and the lowest is the cluster of villages in the Block.
- 3. The Chief Ministers of the concerned States are required to submit annual reports to the Union Home Ministry on the administration of Scheduled Areas in the States.
How many of the above statements are correct?
Answer (b) & explanation
Two statements are correct (b). Statement 1 is right: under paragraph 6 of the Fifth Schedule, the President declares an area a Scheduled Area by order, after consulting the State Governor. Statement 2 is right: Scheduled Areas range from whole districts down to clusters of villages within a block. Statement 3 is wrong: the annual report on Scheduled Areas comes from the Governor, and it goes to the President, not from the Chief Minister to the Home Ministry.
Notice the Tribes Advisory Council, of up to 20 members, three-fourths of them ST members of the State Assembly, which advises on tribal welfare. Ten States have Fifth Schedule areas. The Sixth Schedule covers tribal areas of Assam, Meghalaya, Tripura and Mizoram.
the wrong office (CM for Governor) and the wrong recipient. The Governor is the key figure in the Fifth Schedule.
Answer as per the official UPSC answer key.
With reference to Central Bank digital currencies, consider the following statements :
- 1. It is possible to make payments in a digital currency without using US dollar or SWIFT system.
- 2. A digital currency can be distributed with a condition programmed into it such as a time-frame for spending it.
Which of the statements given above is/are correct?
Answer (c) & explanation
Both statements are correct (c). Statement 1 is right: Central Bank Digital Currencies can be exchanged directly between central banks or users on a shared platform, as tested in projects like mBridge, with no need for the US dollar or the SWIFT messaging network. Statement 2 is right: CBDCs can be programmable: money can be issued only for a set purpose, or with an expiry date, as tested in India's e-rupee pilots for targeted payments such as subsidies.
Notice India's e-rupee, issued by the RBI since December 2022 in wholesale and retail forms. Unlike crypto, a CBDC is legal tender, a direct liability of the central bank. Programmability raises privacy concerns, which the RBI says it will handle carefully.
Answer as per the official UPSC answer key.
Read the passage
More than half of Indian women and almost a quarter of Indian men of working age suffer from anaemia. According to studies, they are anywhere from 5–15% less productive than they could be, as a result thereof. India also has the largest tuberculosis burden in the world, costing 170 million workdays to the country annually. But what is just as important as lost productivity now is lost potential in the future. It is becoming increasingly clear that on many measures of cognitive ability, malnourished Indian children perform two or three times worse than their adequately nourished peers. For an economy that will be more dependent on highly skilled workers, this poses a significant challenge. And it is one that really should be addressed given India’s demographic outlook.
Which one of the following statements best reflects what is implied by the passage ?
Answer (d) & explanation
The implication is that for rapid growth, attention must go to people's health and nutrition (d). Step 1: the passage says anaemia makes workers 5–15% less productive, and TB costs 170 million workdays a year. Step 2: it adds that malnourished children do two or three times worse on cognitive tests, hurting future potential. So health and nutrition drive growth. That is (d). Step 3: option (c) says only skilled workers need attention, which is too narrow. Options (a) and (b) shift to education and skills, which the passage does not discuss.
Tip: the passage links health to productivity both now and in future. Pick the option that covers all the people, not one group.
Answer as per the official UPSC answer key.
Read the passage
There is a claim that organic farming is inherently safer and healthier. The reality is that because the organic farming industry is still young and not well-regulated in India, farmers and consumers, alike, are not only confused about what products are best for them, but sometimes use products in ways that could harm them as well. For example, since organic fertilizers are difficult to obtain on a large scale in India, farmers often use farmyard manure, which may contain toxic chemicals and heavy metals. Certain plant sprays, such as Datura flower and leaf spray, have an element called atropine. If it is not applied in the right dose, it can act on the nervous system of the consumer. Unfortunately, how much and when to use it are not well-researched or regulated issues.
Which one of the following statements best reflects the most logical, rational and practical message conveyed by the author of the passage ?
Answer (c) & explanation
The message is that Indian farmers need guidance and help to make organic farming sustainable (c). Step 1: the passage says the organic industry is "young and not well-regulated". Step 2: doses and timing of sprays are "not well-researched or regulated". So farmers need guidance. That is (c). Step 3: option (a) says organic farming should not be promoted, and option (b) says there are no safe alternatives. Both reject organic farming, which the author does not do. Option (d), profits and global markets, is not discussed.
Tip: a critical passage is not always against the idea. Here the author wants organic farming done right, not stopped.
Answer as per the official UPSC answer key.
A flag has to be designed with 4 horizontal stripes using some or all of the colours red, green and yellow. What is the number of different ways in which this can be done so that no two adjacent stripes have the same colour ?
Answer (c) & explanation
There are 24 ways (c). Step 1: the top stripe can be any of 3 colours. Step 2: each stripe below only has to differ from the one above it, so it has 2 choices. Step 3: 3 × 2 × 2 × 2 = 24. "Some or all" colours means using just two colours (like red-green-red-green) is allowed. Option (d), 36, and the others miscount.
Tip: for "no two adjacent the same", the first item has n choices and each next one has n − 1.
Answer as per the official UPSC answer key.
Consider the following statements :
- 1. Some microorganisms can grow in environments with temperature above the boiling point of water.
- 2. Some microorganisms can grow in environments with temperature below the freezing point of water.
- 3. Some microorganisms can grow in highly acidic environment with a pH below 3.
How many of the above statements are correct?
Answer (c) & explanation
All three statements are correct (c). These microbes are extremophiles. Statement 1 is right: some archaea near deep-sea vents grow above 100°C; water stays liquid there because of high pressure. Methanopyrus kandleri grows at up to 122°C. Statement 2 is right: psychrophiles grow below 0°C in sea ice, glaciers and permafrost, where salt keeps water liquid. Statement 3 is right: acidophiles live in acid mine water and hot springs with a pH near 1.
Notice the uses: the enzyme Taq polymerase, from a hot-spring bacterium, made the PCR test possible, which was used for COVID testing. Extremophiles also suggest where life might exist on other worlds, such as Mars or Jupiter's moon Europa.
Answer as per the official UPSC answer key.
Consider the following statements in relation to Janani Suraksha Yojana :
- 1. It is a safe motherhood intervention of the State Health Departments.
- 2. Its objective is to reduce maternal and neonatal mortality among poor pregnant women.
- 3. It aims to promote institutional delivery among poor pregnant women.
- 4. Its objective includes providing public health facilities to sick infants up to one year of age.
How many of the statements given above are correct?
Answer (b) & explanation
Two statements are correct (b). Statement 2 is right: Janani Suraksha Yojana (2005) aims to cut maternal and newborn deaths among poor pregnant women. Statement 3 is right: it does this by giving them cash to deliver in a hospital or health centre, with ASHA workers guiding them. Statement 1 is wrong: it is a safe-motherhood intervention under the National Health Mission of the Union Health Ministry, not a scheme of the State health departments, though States run it. Statement 4 is wrong: free care for sick infants up to one year comes under the separate Janani Shishu Suraksha Karyakram (JSSK, 2011).
Notice the result: institutional deliveries rose to about 89% by NFHS-5, and India's maternal mortality ratio has fallen below 100 per lakh live births.
Answer as per the official UPSC answer key.
Consider the following statements in respect of the National Flag of India according to the Flag Code of India, 2002 :
Statement-I :
- One of the standard sizes of the National Flag of India is 600 mm × 400 mm.
Statement-II :
- The ratio of the length to the height (width) of the Flag shall be 3 : 2.
Which one of the following is correct in respect of the above statements?
Answer (d) & explanation
Statement I is wrong but Statement II is correct (d). Statement II is right: the Flag Code of India, 2002 fixes the ratio of length to height at 3 : 2. Statement I is wrong: the Code lists nine standard sizes, from 6300 × 4200 mm down to 150 × 100 mm. Sizes near the middle include 900 × 600 and 450 × 300, but 600 × 400 is not on the list, even though it keeps the ratio.
Notice recent changes. In 2021–22, the Code was amended to allow machine-made and polyester flags, and to let the flag fly day and night when hoisted in the open by the public, for the Har Ghar Tiranga campaign. The Supreme Court held in Naveen Jindal (2004) that flying the flag is part of free expression.
a size that fits the 3 : 2 ratio. Fitting the ratio does not make it a standard size.
Answer as per the official UPSC answer key.
Read the passage
Many people are not eating the right food. For some, it is simply a decision to stick with food they enjoy but which is not too healthy. This is leading to an increase in non-communicable diseases. This in turn leads to major burden on our health-care systems that have the potential to derail the economic progress which is essential for the poor to improve their lives. For others, it is about limited access to nutritious food or a lack of affordability, leading to monotonous diets that do not provide the daily nutrients for them to develop fully. Part of the reason nutrition is under threat worldwide is that our food systems are not properly responding to nutritional needs. Somewhere along that long road from farm to fork, there are serious detours taking place.
Which one of the following statements best reflects the crux of the passage ?
Answer (b) & explanation
The crux is that food-based nutrition must be at the centre of policy debate (b). Step 1: the passage says many people eat unhealthy food, which raises non-communicable diseases. Others lack access to nutritious food. Step 2: it says our food systems are not responding to nutritional needs, with "detours" from farm to fork. So nutrition must come first in food policy. That is (b). Step 3: option (a), Universal Basic Income, is not mentioned. Options (c) GM crops and (d) food fortification are specific fixes the passage does not propose.
Tip: the crux is the broad idea the passage builds to. Options naming specific technologies are usually too narrow.
Answer as per the official UPSC answer key.
How many natural numbers are there which give a remainder of 31 when 1186 is divided by these natural numbers ?
Answer (d) & explanation
There are 9 such numbers (d). Step 1: if 1186 leaves remainder 31, then the divisor n divides 1186 − 31 = 1155. Also, n must be greater than 31 (a remainder is always smaller than the divisor). Step 2: 1155 = 3 × 5 × 7 × 11, which has 2 × 2 × 2 × 2 = 16 divisors. Step 3: those above 31 are 33, 35, 55, 77, 105, 165, 231, 385 and 1155. That is 9. Options (a), (b) and (c) miss some.
Tip: never forget the rule that the divisor must exceed the remainder. It removes the small divisors.
a remainder of 31 needs a divisor larger than 31. Counting all 16 divisors is the trap.
Answer as per the official UPSC answer key.
Consider the following statements in respect of five candidates P, Q, R, S and T. Two statements are true and one statement is false.
True Statement : One of P and Q was selected for the job.
False Statement : At least one of R and S was selected for the job.
True Statement : At most two of R, S and T were selected for the job.
Which of the following conclusions can be drawn ?
- 1. At least four were selected for the job.
- 2. S was selected for the job.
Select the correct answer using the code given below :
Answer (d) & explanation
Neither conclusion follows (d). Step 1: the false statement is "at least one of R and S was selected". If it is false, then neither R nor S was selected. So conclusion 2 (S was selected) is wrong. Step 2: only one of P and Q was selected, and T may or may not be. So at most 2 people were selected. Step 3: so conclusion 1 (at least four selected) is wrong too. Options (a), (b) and (c) fail.
Tip: the opposite of "at least one" is "none". Turning the false statement into its opposite is the key step.
the negation of 'at least one' is 'none', not 'only one'.
Answer as per the official UPSC answer key.
Consider the following :
- 1. Demographic performance
- 2. Forest and ecology
- 3. Governance reforms
- 4. Stable government
- 5. Tax and fiscal efforts
For the horizontal tax devolution, the Fifteenth Finance Commission used how many of the above as criteria other than population, area and income distance?
Answer (b) & explanation
Three of the five were criteria (b). The 15th Finance Commission, chaired by N.K. Singh, shared central taxes among States using: income distance 45%, population (2011 Census) 15%, area 15%, forest and ecology 10%, demographic performance 12.5% and tax and fiscal effort 2.5%. So items 1, 2 and 5 count. Item 3 is wrong: governance reforms was not a criterion. Item 4 is wrong: stable government was never used. The States' total share was 41% of the divisible pool.
Notice that demographic performance rewards States that brought down fertility, mostly southern States, which feared losing out by the use of the 2011 Census. The 16th Finance Commission, chaired by Arvind Panagariya, covers 2026–31.
Answer as per the official UPSC answer key.
With reference to the Earth’s atmosphere, which one of the following statements is correct?
Answer (c) & explanation
Infrared is largely absorbed by water vapour in the lower atmosphere (c). Option (c) is right: water vapour, which is concentrated near the surface, and carbon dioxide absorb most of the infrared heat, which is why they are greenhouse gases. Option (a) is wrong: the equator gets only about 2.5 times the yearly insolation of the poles, not 10 times. Option (b) is wrong: infrared is roughly half of incoming sunlight, not two-thirds; visible light is a large share too. Option (d) is wrong: infrared lies outside the visible band, beyond red.
Notice why the air is heated from below: sunlight passes through, warms the ground, and the ground gives off infrared that the lower air absorbs. That is why temperature falls with height in the troposphere.
Answer as per the official UPSC answer key.
Consider the following pairs with regard to sports awards :
- 1. Major Dhyan Chand Khel Ratna Award : For the most spectacular and outstanding performance by a sportsperson over period of last four years
- 2. Arjuna Award : For the lifetime achievement by a sportsperson
- 3. Dronacharya Award : To honour eminent coaches who have successfully trained sportspersons or teams
- 4. Rashtriya Khel Protsahan Puraskar : To recognize the contribution made by sportspersons even after their retirement
How many of the above pairs are correctly matched?
Answer (b) & explanation
Two pairs are correctly matched (b). Pair 1 is right: the Major Dhyan Chand Khel Ratna honours the most spectacular and outstanding performance by a sportsperson over the last four years. Pair 3 is right: the Dronacharya Award honours eminent coaches who have trained winning sportspersons or teams. Pair 2 is wrong: the Arjuna Award is for consistent good performance over four years; lifetime achievement is honoured by the Dhyan Chand Award, now the Arjuna Award (Lifetime). Pair 4 is wrong: the Rashtriya Khel Protsahan Puraskar goes to organisations and corporates that promote sport, not retired players.
Notice that the Khel Ratna was renamed from Rajiv Gandhi to Major Dhyan Chand in 2021. The MAKA Trophy goes to the best university in sport.
Answer as per the official UPSC answer key.
If 7 ⊕ 9 ⊕ 10 = 8, 9 ⊕ 11 ⊕ 30 = 5, 11 ⊕ 17 ⊕ 21 = 13, what is the value of 23 ⊕ 4 ⊕ 15 ?
Answer (a) & explanation
The value is 6 (a). Step 1: find the rule from the examples. Add the three numbers, then add the digits of the sum. Step 2: 7 + 9 + 10 = 26 → 2 + 6 = 8. 9 + 11 + 30 = 50 → 5. 11 + 17 + 21 = 49 → 4 + 9 = 13. The rule works for all three. Step 3: 23 + 4 + 15 = 42 → 4 + 2 = 6. Options (b), (c) and (d) do not follow this rule.
Tip: for made-up symbols, test simple operations (sum, product, digit sum) on all examples. The rule must fit every one.
Answer as per the official UPSC answer key.