UPSC Prelims PYQs with explanations
Real questions from official papers, mapped to syllabus topics. Attempt each one; the answer and the reason appear instantly.
Let A, B and C represent distinct non-zero digits. Suppose x is the sum of all possible 3-digit numbers formed by A, B and C without repetition.
Consider the following statements :
- 1. The 4-digit least value of x is 1332.
- 2. The 3-digit greatest value of x is 888.
Which of the above statements is/are correct?
Answer (a) & explanation
1. Six numbers can be made (ABC, ACB, BAC, BCA, CAB, CBA). Each digit sits twice in the hundreds place, twice in the tens and twice in the units.
2. So x = 222 × (A + B + C). Check with 1, 2, 3: 123 + 132 + 213 + 231 + 312 + 321 = 1332, and 222 × 6 = 1332.
3. The smallest A + B + C is 1 + 2 + 3 = 6, so the smallest x is 1332. Statement 1 is true.
4. Since x is at least 1332, it is never a 3-digit number. Statement 2 is false.
Answer as per the official UPSC answer key.
With reference to foreign-owned e-commerce firms operating in India, which of the following statements is/are correct ?
- 1. They can sell their own goods in addition to offering their platforms as market-places.
- 2. The degree to which they can own big sellers on their platforms is limited.
Select the correct answer using the code given below :
Answer (d) & explanation
Neither statement is correct (d). India allows 100% FDI in e-commerce only in the marketplace model, where the platform connects buyers and sellers. Statement 1 is wrong: a foreign-owned platform may not hold its own inventory and sell its own goods; the inventory model is barred for FDI. Statement 2 is wrong as worded: since the 2018 rules, a seller in which the platform or its group has any equity cannot sell on that platform at all. This is a ban, not a limit on the degree of ownership.
Notice that the rules targeted Amazon and Flipkart (Walmart). India also built ONDC (Open Network for Digital Commerce, 2022), a government-backed open network meant to give small sellers a fairer chance.
statement 2 sounds mild and true. The rule does not limit such ownership; it bars those sellers outright.
Answer as per the official UPSC answer key.
If a major solar storm (solar flare) reaches the Earth, which of the following are the possible effects on the Earth ?
- 1. GPS and navigation systems could fail.
- 2. Tsunamis could occur at equatorial regions.
- 3. Power grids could be damaged.
- 4. Intense auroras could occur over much of the Earth.
- 5. Forest fires could take place over much of the planet.
- 6. Orbits of the satellites could be disturbed.
- 7. Shortwave radio communication of the aircraft flying over polar regions could be interrupted.
Select the correct answer using the code given below :
Answer (c) & explanation
Effects 1, 3, 4, 6 and 7 are possible (c). A big solar storm disturbs Earth's ionosphere and magnetic field. Item 1 is right: it disrupts GPS and navigation signals. Item 3 is right: it induces currents that can damage power grids, as in Quebec in 1989. Item 4 is right: it spreads auroras to low latitudes. Item 6 is right: it heats the upper air, which drags satellites down; SpaceX lost about 40 Starlink satellites in 2022. Item 7 is right: it blocks shortwave (HF) radio over the poles. Items 2 and 5 are wrong: it cannot cause tsunamis or forest fires.
Notice the Carrington Event (1859), the strongest storm on record. India's Aditya-L1 (2023) studies the Sun from the L1 point.
Remove the two impossible effects, tsunamis and forest fires. Only option (c) is left.
Answer as per the official UPSC answer key.
If a particular area is brought under the Fifth Schedule of the Constitution of India, which one of the following statements best reflects the consequence of it?
Answer (a) & explanation
Fifth Schedule status protects tribal land (a). Paragraph 5(2) of the Fifth Schedule lets the Governor make regulations for Scheduled Areas that can prohibit or restrict the transfer of tribal land to non-tribals, and control money-lending. Option (b) is wrong: autonomous district councils are part of the Sixth Schedule, used in Assam, Meghalaya, Tripura and Mizoram. Option (c) is wrong: a Scheduled Area stays part of its State; it does not become a Union Territory. Option (d) is wrong: Special Category status came from the old Planning Commission criteria, not from the Fifth Schedule.
Notice the link with PESA, 1996, which gives gram sabhas in Fifth Schedule areas power over minor forest produce and land. Ten states now have Fifth Schedule areas.
option (b) describes the Sixth Schedule's autonomous councils. Keep the two Schedules apart.
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.
Unsustainability in production pattern is due to which of the following?
- 1. Heavy dependence on fossil fuels
- 2. Limited availability of resources
- 3. Expansion of recycling
Select the correct answer using the code given below.
Answer (a) & explanation
Statements 1 and 2 are the causes (a). Step 1: the passage says current production "relies heavily on fossil fuels" (1). Step 2: it says this is unsustainable "because the resources are finite", meaning limited (2). Step 3: recycling appears as something developed countries do to reduce the harm. It is a remedy, not a cause, so statement 3 fails. That rules out options (c) and (d). Option (b) misses statement 1.
Tip: in cause questions, separate the problem from the cure. A passage often mentions both, and UPSC places the cure among the causes as a trap.
Answer as per the official UPSC answer key.
Read the passage
Natural selection cannot anticipate future environments on the earth. Therefore, the set of existing organisms can never be fully prepared for environmental catastrophes that await life. An outcome of this is the extinction of those species which cannot overcome environmental adversity. This failure to survive, in modern terms, can be attributed to the genomes which are unable to withstand geological vagaries or biological mishaps (infections, diseases and so on). In biological evolution on the earth, extinction of species has been a major feature. The earth may presently have up to ten million species, yet more than 90% of species that have ever lived on the earth are now extinct. Once again, the creationist doctrines fail to satisfactorily address why a divine creator will firstly bother to create millions of species and then allow them to perish. The Darwinian explanation for extinct life is once again simple, elegant and at once convincing—organisms go extinct as a function of environmental or biological assaults for which their inheritance deems them ill-equipped. Therefore, the so-called Darwinian theory of evolution is not a theory at all. Evolution happens—this is a fact. The mechanism of evolution (Darwin proposed natural selection) is amply supported by scientific data. Indeed, to date no single zoological, botanical, geological, paleontological, genetic or physical evidence has refuted either of the central two main Darwinian ideas. If religion is not taken into consideration, Darwinian laws are acceptable just like the laws proposed by Copernicus, Galileo, Newton and Einstein—sets of natural laws that explain natural phenomena in the universe.
With reference to the passage, the following assumptions have been made :
- 1. Only species that have the ability to overcome environmental catastrophes will survive and perpetuate.
- 2. More than 90% of the species on the earth are in the danger of getting extinct due to drastic changes in the environment.
- 3. Darwin’s theory explains all the natural phenomena.
Which of the above assumptions is/are valid?
Answer (a) & explanation
Only assumption 1 is valid (a). Step 1: the passage says species that cannot overcome environmental adversity go extinct. So only those that can overcome it survive (1). Step 2: assumption 2 misreads the 90% figure. The passage says 90% of species that ever lived are now extinct, not that 90% of today's species are in danger. Step 3: assumption 3 says Darwin's theory explains all natural phenomena; this overreaches. So options (b), (c) and (d) fail.
Tip: check what a number refers to. UPSC often changes "species that ever lived" into "species on earth now" to set a trap.
Answer as per the official UPSC answer key.
What is the smallest number greater than 1000 that when divided by any one of the numbers 6, 9, 12, 15, 18 leaves a remainder of 3?
Answer (c) & explanation
The number is 1083 (c). Step 1: a number leaving remainder 3 for each divisor is 3 more than a common multiple. LCM(6, 9, 12, 15, 18) = 180. Step 2: so the number is 180k + 3. Step 3: 180 × 5 + 3 = 903 is below 1000. 180 × 6 + 3 = 1083 is the first above 1000. Options (a) 1063 and (b) 1073 are not 3 more than a multiple of 180. Option (d), 1183, is not either.
Tip: "same remainder r for all divisors" means the number = LCM × k + r. Find the LCM first.
Answer as per the official UPSC answer key.
With reference to Ayushman Bharat Digital Mission, consider the following statements :
- 1. Private and public hospitals must adopt it.
- 2. As it aims to achieve universal health coverage, every citizen of India should be part of it ultimately.
- 3. It has seamless portability across the country.
Which of the statements given above is/are correct ?
Answer (b) & explanation
Only statement 3 is correct (b). The Ayushman Bharat Digital Mission (2021) builds digital health infrastructure: the ABHA (Ayushman Bharat Health Account) health ID, and registries of health professionals and facilities. Statement 1 is wrong: joining is voluntary for both private and public hospitals. Statement 2 is wrong: it is also voluntary for citizens; no one must take an ABHA ID. Statement 3 is right: records linked to ABHA are portable across hospitals, labs and States, with the patient's consent.
Notice that ABDM is run by the National Health Authority, which also runs AB-PMJAY, the health insurance scheme of ₹5 lakh a family. In 2024, PMJAY was extended to all citizens aged 70 and above.
"Must" and "every citizen" are the words that rule out statements 1 and 2.
Answer as per the official UPSC answer key.
In the Government of India Act 1919, the functions of Provincial Government were divided into “Reserved” and “Transferred” subjects. Which of the following were treated as “Reserved” subjects ?
- 1. Administration of Justice
- 2. Local Self-Government
- 3. Land Revenue
- 4. Police
Select the correct answer using the code given below :
Answer (c) & explanation
Justice, land revenue and police were "Reserved" (c). The Government of India Act 1919 (Montagu–Chelmsford reforms) brought dyarchy to the provinces. The Governor and his executive council kept the reserved subjects, the ones that held real power: police, law and order, administration of justice, land revenue, irrigation and finance. Indian ministers answerable to the legislature got the transferred subjects. Item 2 is wrong: local self-government was transferred, along with education, public health and agriculture. So any option with item 2, that is (a), (b) and (d), falls.
Notice the trick: the British gave Indians the departments that needed money but kept the purse and the police. Dyarchy at the provinces was later ended by the 1935 Act, which moved it to the Centre.
Answer as per the official UPSC answer key.
Consider the following statements :
- 1. Gujarat has the largest solar park in India.
- 2. Kerala has a fully solar powered International Airport.
- 3. Goa has the largest floating solar photovoltaic project in India.
Which of the statements given above is/are correct ?
Answer (b) & explanation
Only statement 2 is correct (b). Statement 2 is right: Cochin International Airport in Kerala became the world's first fully solar-powered airport in 2015. Statement 1 was wrong when asked: the largest commissioned solar park was Bhadla in Rajasthan, at about 2,245 MW. Gujarat's giant Khavda renewable park is now being built to reach 30 GW, but that came later. Statement 3 is wrong: large floating solar plants are at Ramagundam (Telangana) and Omkareshwar (Madhya Pradesh), not in Goa.
Notice India's target of 500 GW of non-fossil power capacity by 2030. Floating solar saves land and cuts evaporation from reservoirs. The PM Surya Ghar scheme (2024) pushes rooftop solar in homes.
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 the methodology adopted in India to count the ‘poor’ debatable?
Answer (d) & explanation
The method is debatable because it rests only on poverty as low income or buying power (d). Step 1: the passage says the poverty line "exclusively relies on the notion of poverty as insufficient income or insufficient purchasing power". Step 2: this narrow base is the fundamental problem. That is (d). Step 3: option (a), confusion over the line, is not the stated reason. Option (b), rural-urban diversity, and option (c), lack of a global standard, are outside the passage.
Tip: this passage draws on Amartya Sen's capability approach. India's NITI Aayog now also uses a Multidimensional Poverty Index alongside income measures.
Answer as per the official UPSC answer key.
Read the passage
The demographic dividend, which has begun in India and is expected to last another few decades, is a great window of opportunity. The demographic dividend is basically a swelling in the working age population, which conversely means that the relative ratio of very young and very old will, for a while, be on the decline. From the experience of Ireland and China, we know that this can be a source of energy and an engine of economic growth. The demographic dividend tends to raise a nation’s savings rate since in any nation, it is the working age population that is the main saver. And since the savings rate is an important driver of growth, this should help elevate our growth rate. However, the benefits of demographic dividend depend on the quality of the working age population. And this implies bringing back the importance of education, acquisition of skills and human capital.
With reference to the passage, which of the following inferences can be drawn?
- 1. Demographic dividend is an essential condition for a country to rapidly increase its economic growth rate.
- 2. Promotion of higher education is an essential condition for a country for its rapid economic growth.
Select the correct answer using the code given below.
Answer (d) & explanation
Neither inference can be drawn (d). Step 1: the passage says the demographic dividend "can be" an engine of growth. It does not say growth is impossible without it. So it is not an essential condition (1 fails). Step 2: the passage stresses education, skills and human capital in general. It does not single out higher education as essential (2 fails). Step 3: so options (a), (b) and (c) fail.
Tip: "can be a source" is not "is a necessary condition". India's working-age population share is expected to stay high for the next few decades, making skills the key.
Answer as per the official UPSC answer key.
One non-zero digit, one vowel and one consonant from English alphabet (in capital) are to be used in forming passwords, such that each password has to start with a vowel and end with a consonant. How many such passwords can be generated?
Answer (c) & explanation
945 passwords can be made (c). Step 1: the password starts with a vowel and ends with a consonant. So the order is fixed: vowel, digit, consonant. Step 2: there are 5 vowels, 9 non-zero digits and 21 consonants. Step 3: 5 × 9 × 21 = 945. Option (d), 1050, uses 10 digits (including 0). Options (a) and (b) leave out a factor.
Tip: when positions are fixed, simply multiply the choices for each place. Check "non-zero" carefully: it removes one digit.
Answer as per the official UPSC answer key.
Consider the following pairs :
| Wetland / Lake | Location
| 1. Hokera Wetland | Punjab
| 2. Renuka Wetland | Himachal Pradesh
| 3. Rudrasagar Lake | Tripura
| 4. Sasthamkotta Lake | Tamil Nadu
How many pairs given above are correctly matched ?
Answer (b) & explanation
Only two pairs are correct (b). All four are Ramsar sites. Pair 2 is right: Renuka wetland is in Sirmaur, Himachal Pradesh, named after the mother of Parashurama. Pair 3 is right: Rudrasagar lake is in Tripura, home to the Neermahal water palace. Pair 1 is wrong: Hokera wetland is near Srinagar in Jammu and Kashmir, not Punjab. Pair 4 is wrong: Sasthamkotta, the largest freshwater lake in Kerala, is in Kollam, not Tamil Nadu.
Notice that India has rapidly added Ramsar sites, reaching over 90 by 2025; Tamil Nadu has the most. The Ramsar Convention was signed in Iran in 1971, and World Wetlands Day is on 2 February. Chilika was India's first site (1981).
Punjab has several Ramsar sites (Harike, Kanjli), so a Punjab label looks safe.
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Answer as per the official UPSC answer key.
Consider the following statements :
- 1. In India, credit rating agencies are regulated by Reserve Bank of India.
- 2. The rating agency popularly known as ICRA is a public limited company.
- 3. Brickwork Ratings is an Indian credit rating agency.
Which of the statements given above are correct ?
Answer (b) & explanation
Statements 2 and 3 are correct (b). Statement 2 is right: ICRA began in 1991 as the Investment Information and Credit Rating Agency and is a public limited company listed on the stock exchanges; Moody's is its major shareholder. Statement 3 is right: Brickwork Ratings was an Indian credit rating agency set up in Bengaluru, though SEBI cancelled its registration in 2022 for lapses. Statement 1 is wrong: credit rating agencies are registered and regulated by SEBI under the CRA Regulations, 1999, not by the RBI. The RBI only lists which agencies banks may use for capital rules.
Notice the other Indian agencies: CRISIL (S&P), CARE, India Ratings (Fitch) and Acuité.
ratings are used by banks, so the RBI comes to mind. The RBI only accredits agencies for bank capital rules; SEBI regulates them.
Answer as per the official UPSC answer key.
The Prime Minister recently inaugurated the new Circuit House near Somnath Temple at Veraval. Which of the following statements are correct regarding Somnath Temple ?
- 1. Somnath Temple is one of the Jyotirlinga shrines.
- 2. A description of Somnath Temple was given by Al-Biruni.
- 3. Pran Pratishtha of Somnath Temple (installation of the present day temple) was done by President S. Radhakrishnan.
Select the correct answer using the code given below :
Answer (a) & explanation
Statements 1 and 2 are correct (a). Statement 1 is right: Somnath at Prabhas Patan in Gujarat is the first of the twelve Jyotirlingas of Shiva. Statement 2 is right: Al-Biruni, who came with Mahmud of Ghazni, described the temple and its linga after Mahmud's 1025 raid. Statement 3 is wrong: the rebuilt temple, pushed by Sardar Patel and K.M. Munshi, was consecrated in May 1951 by President Rajendra Prasad, not S. Radhakrishnan.
Notice the debate around the event: Nehru advised against the President attending, but Prasad went anyway. That is a well-known episode on the line between state and religion. Al-Biruni's Kitab-ul-Hind is a major source on 11th-century Indian society, science and beliefs.
Answer as per the official UPSC answer key.
Read the passage
In some places in the world, the productivity of staples such as rice and wheat has reached a plateau. Neither new strains nor fancy agrochemicals are raising the yields. Nor is there much unfarmed land left that is suitable to be brought under the plough. If global temperature continues to rise, some places will become unsuitable for farming. Application of technology can help overcome these problems. Agricultural technology is changing fast. Much of this change is brought about by affluent farmers in the West/Americas. Techniques developed in the West are being adapted in some places to make tropical crops more productive. Technology is of little use if it is not adapted. In the developing world, that applies as much to existing farming techniques as it does to the latest advances in genetic modification. Extending to the smallholders and subsistence farmers of Africa and Asia the best of today’s agricultural practices, in such simple matters as how much fertilizers to apply and when, would lead to a greatly increased availability of food for humanity. So would things like better roads and storage facilities, to allow for the carriage of surpluses to markets and reduce wastage.
Based on the above passage, the following assumptions have been made :
- 1. Growing enough food for future generations will be a challenge.
- 2. Corporate farming is a viable option for food security in poor countries.
Which of the above assumptions is/are valid?
Answer (a) & explanation
Only assumption 1 is valid (a). Step 1: the passage says yields have plateaued, little spare land is left, and warming may make places unfit for farming. So growing enough food in future will be a challenge (1). Step 2: the passage favours helping smallholders and subsistence farmers. Corporate farming is never raised (2). Step 3: so options (b), (c) and (d) fail.
Tip: if the passage's solution is "help small farmers", an option pushing a different model (corporate farming) is outside it.
Answer as per the official UPSC answer key.
There is a numeric lock which has a 3-digit PIN. The PIN contains digits 1 to 7. There is no repetition of digits. The digits in the PIN from left to right are in decreasing order. Any two digits in the PIN differ by at least 2. How many maximum attempts does one need to find out the PIN with certainty?
Answer (c) & explanation
At most 10 attempts are needed (c). Step 1: the digits go from big to small. So once three digits are chosen, the PIN is fixed. We only need to count the choices. Step 2: list sets from 1 to 7 where any two digits differ by at least 2: 531, 631, 641, 642, 731, 741, 742, 751, 752, 753. Step 3: that is 10 PINs, so 10 attempts make it certain. Options (a), (b) and (d) miscount.
Tip: when order is forced (decreasing), arrangements become combinations. A shortcut: choose 3 from 7 with gaps of 2 = C(5, 3) = 10.
Answer as per the official UPSC answer key.
Which of the following activities constitute real sector in the economy ?
- 1. Farmers harvesting their crops
- 2. Textile mills converting raw cotton into fabrics
- 3. A commercial bank lending money to a trading company
- 4. A corporate body issuing Rupee Denominated Bonds overseas
Select the correct answer using the code given below :
Answer (a) & explanation
Harvesting crops and making fabric are real sector activities (a). The real sector produces goods and services: farming, mining, manufacturing, construction and the like. Item 1 is right: farmers harvesting crops produce real goods. Item 2 is right: textile mills turning cotton into fabric create real output. Item 3 is wrong: a bank lending money is a financial sector activity; it moves money, not goods. Item 4 is wrong: a firm issuing Rupee Denominated Bonds overseas, called masala bonds, is also a financial activity.
Notice that GDP counts real output; the financial sector adds value through its services, but its transfers of money are not new goods. The Twin Balance Sheet problem linked stressed real-sector firms with stressed banks.
Answer as per the official UPSC answer key.
“Climate Action Tracker” which monitors the emission reduction pledges of different countries is a:
Answer (a) & explanation
It is a database created by research organisations (a). The Climate Action Tracker is run by two independent research groups, Climate Analytics and the NewClimate Institute. It rates each country's pledges (NDCs), targets and policies against the Paris Agreement goal of keeping warming to 1.5 °C, using grades from "critically insufficient" to "1.5 °C compatible". Option (b) is wrong: it is not part of the IPCC. Option (c) is wrong: it is not a UNFCCC committee. Option (d) is wrong: it is not run or funded by UNEP and the World Bank.
Notice the official tools: NDCs submitted every five years, and the Global Stocktake, the first of which ended at COP28 (Dubai, 2023). India's updated NDC targets net zero by 2070.
Answer as per the official UPSC answer key.