99 previous year UPSC Prelims questions on the UPSC 2025 Prelims. Choose an option to see the answer and explanation.
Explanations state facts as of the year each question was asked; words like “recently” refer to that year.
Showing 61–70 of 99 questions
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UPSC 2025Science and Technology · Miscellaneous
Q61. Consider the following statements: Statement I: Some rare earth elements are used in the manufacture of flat television, screens and computer monitors. Statement II: Some rare earth elements have phosphorescent properties. Which one of the following is correct in respect of the above statements?
Explanation
Rare earth elements (REEs) are a group of 17 chemically similar metallic elements that are known for their high luster, high density, and unique magnetic, phosphorescent, and catalytic properties.
Statement 1 is correct: Rare earth elements such as europium, terbium, and yttrium are crucial for producing the bright, vivid colors in modern flat screens and monitors.
Statement 2 is correct: Many rare earth elements, like europium and terbium, have phosphorescent or luminescent properties, meaning they can absorb energy and emit light, which is used in various applications including displays.
Additional insight:
Uses of Rare-earth Metals Rare-earth metals play a vital role across multiple sectors, including electronics, renewable energy, and automotive industries. They are indispensable for manufacturing high-performance magnets used in electric vehicle motors and wind turbines, and are also key components in efficient lighting like fluorescent lamps. In electronics, rare-earth metals are essential for producing smartphones, computers, and other devices, enabling smaller sizes, better performance, and greater energy efficiency. Their unique magnetic and catalytic properties also make them crucial for renewable energy technologies, such as wind turbines, solar panels, and electric vehicle batteries, enhancing the effectiveness and sustainability of these systems.
Exam tip:
Anytime a statement uses "some" (not "all"), it makes it logically hard to disprove. Hence likely true. Combine that with cause-effect linkage (screens need light rare earths emit light), and you arrive at the right answer option A.
UPSC 2025Indian Economy · Industry
Q62. Consider the following statements: I. Indian Railways have prepared a National Rail Plan (NRP) to create a ‘future ready’ railway system by 2028. II. ‘Kavach’ is an Automatic Train Protection system developed in collaboration with Germany. III. ‘Kavach’ system consists of RFID tags fitted on track in station section. Which of the statements given above are not correct?
Explanation
Statement 1 is incorrect: The National Rail Plan aims to create a ‘future ready’ railway system by 2030, not 2028. The objective of the Plan is to create capacity ahead of demand, which in turn would also cater to future growth in demand right up to 2050 and also increase the modal share of Railways to 45% in freight traffic and to continue to sustain it.
Statement 2 is incorrect: ‘Kavach’ is an indigenously developed Automatic Train Protection (ATP) system by Indian Railways, not in collaboration with Germany. The name "Kavach," meaning "shield" in Hindi, reflects its purpose of delivering robust protection and upholding top safety standards in railway operations. With its certification at the highly regarded Safety Integrity Level 4 (SIL-4), Kavach demonstrates outstanding reliability.
Statement 3 is correct: Radio Frequency Identification (RFID) tags are placed throughout the entire track length to enable the Kavach system to track train positions and detect any potential safety issues along the route.
Additional insight:
Automatic Train Protection (ATP) is a train safety system designed to ensure that a train’s speed remains within the limits set by the signalling system. It continuously monitors the train’s speed and automatically enforces compliance with permitted speed restrictions. If the train exceeds the allowed speed or fails to respond to specific signal aspects, ATP promptly activates the emergency brakes to bring the train to a stop. Tolerable Hazard Rate (THR) and Safety Integrity Levels (SIL):
The Tolerable Hazard Rate (THR) acts as a benchmark for evaluating safety-related failures. THR evaluates both systematic and random safety-related failures within a system. It establishes a quantitative framework to define the required safety level, ensuring compliance with acceptable risk standards. Safety integrity is classified into four tiers, ranging from SIL 4 (highest safety assurance) to SIL 0 (no mandated safety measures). A Safety Integrity Level (SIL) is determined through a qualitative review of factors such as safety protocols, quality management systems, and technical safeguards. Attaining the correct SIL is crucial for mitigating risks posed by systematic flaws and random operational failures.
UPSC 2025Science and Technology · Space and Space Technology
Q63. Consider the following space missions: I. Axiom-4 II. SpaDeX III. Gaganyaan How many of the space missions given above encourage and support micro-gravity research?
Explanation
Microgravity research refers to scientific studies conducted in environments where the force of gravity is extremely low, causing objects and people to appear weightless. In such conditions, often found in space or simulated on Earth, researchers can observe how physical, chemical, and biological systems behave differently than they do under normal gravity. Options 1, 2, and 3 are correct:
Axiom-4 is a private mission to the ISS that will conduct around 60 scientific studies, including several led by ISRO, with a strong focus on microgravity research across various disciplines such as biology, medicine, and materials science. ISRO and ESA are collaborating on microgravity research experiments specifically for Axiom-4. SpaDeX is an ISRO technology demonstrator for in-space docking. The mission uses the PSLV’s fourth stage (POEM-4) to carry 24 payloads from academia and startups, which will utilize the microgravity environment in orbit for scientific experiments. The mission explicitly provides opportunities for in-orbit microgravity experiments for extended durations. Gaganyaan is India’s first human spaceflight mission, led by ISRO. Scheduled to send Indian astronauts into low Earth orbit, it aims to demonstrate indigenous capability in crewed space missions. Gaganyaan will also facilitate scientific research in microgravity, marking a significant milestone in India’s space exploration journey.
Exam tip:
If a mission goes to space (especially to ISS or LEO), microgravity is either used, tested, or researched -- even if not the main goal. Hence, All three missions likely qualify to encourage and support micro-gravity research under this logic.
UPSC 2025Science and Technology · Defence Technology
Q64. With reference to India’s defence, consider the following pairs:
Aircraft type
Description
I. Dornier-228
Maritime patrol aircraft
II. IL-76
Supersonic combat aircraft
III. C-17 Globemaster III
Military transport aircraft
How many of the pairs given above are correctly matched?
Explanation
Pair 1 is correctly matched: Dornier -228 is known for their versatility, they are equipped for a range of missions, including maritime patrol, surveillance, pollution control, search and rescue, and medical evacuation.
Pair 2 is not correctly matched: The Ilyushin Il-76 is a strategic/heavy military transport aircraft, not a supersonic combat aircraft. HAL Tejas, MiG-21, Sukhoi Su-30MKI and Dassault Rafale are examples of supersonic combat aircraft.
Pair 3 is correctly matched: The C-17 Globemaster III is a large military transport aircraft used for airlift and cargo missions. The Indian Air Force (IAF) has received its third Boeing C-17 Globemaster III, a large, versatile military transport aircraft capable of carrying heavy, oversize loads long distances and landing on rough and unprepared surfaces.
Additional insight:
Maritime Patrol Aircraft: A maritime patrol aircraft is a fixed-wing aircraft designed for extended operations over water, primarily performing maritime surveillance, anti-submarine warfare, anti-ship warfare, and search and rescue missions. They are equipped with sensors like radar, sonobuoys, and magnetic anomaly detectors for effective maritime reconnaissance. Supersonic Combat Aircraft: Supersonic combat aircraft are military jets capable of flying faster than the speed of sound (Mach 1). These aircraft, such as fighter jets, are designed for air-to-air or air-to-ground combat and utilize advanced aerodynamics to operate efficiently at supersonic speeds. Military Transport Aircraft: Military transport aircraft, also known as airlifters, are used to move troops, equipment, and supplies to support military operations. They play a vital role in maintaining supply lines, conducting strategic and tactical missions, and providing humanitarian aid during emergencies.
UPSC 2025Environment and Ecology · Pollution
Q65. Artificial way of causing rainfall to reduce air pollution makes use of
Explanation
Cloud-seeding is a technique used to modify weather by releasing silver iodide (AgI) into the atmosphere to facilitate the formation of ice crystals, enhancing the cloud’s ability to generate rain. In the process of cloud-seeding, chemicals like silver iodide, potassium iodide, and dry ice are dispersed into the sky via airplanes and helicopters.
Additional insight:
Cloud seeding is divided into two main types:
Hygroscopic Cloud Seeding: This approach promotes the growth of water droplets in liquid clouds by introducing salt particles, typically at the cloud’s base, which helps the droplets combine and become heavy enough to fall as rain. Glaciogenic Cloud Seeding: This method encourages the formation of ice crystals in supercooled clouds by releasing substances such as silver iodide or dry ice, which serve as ice nuclei, initiating ice formation and ultimately leading to precipitation.
UPSC 2025Polity · President
Q66. Consider the following statements with regard to pardoning power of the President of India: I. The exercise of this power by the President can be subjected to limited judicial review. II. The President can exercise this power without the advice of the Central Government. Which of the statements given above is/are correct?
Explanation
Statement 1 is correct: While the President’s pardoning power is broad, it is not absolute. The Supreme Court has held that judicial review is permissible if the decision is arbitrary, mala fide, or based on irrelevant considerations (e.g., political favoritism). In the landmark case of Maru Ram v. Union of India (1980) it was established that courts can intervene if constitutional principles are violated.
Statement 2 is incorrect: In the Maru Ram v. Union of India case, the Supreme Court made it clear that the President’s power to grant pardons under Article 72 is an executive responsibility and must be carried out based on the advice of the Council of Ministers, as required by Article 74. The President does not have the authority to use this power independently.
Exam tip:
For S1, it is a well known fact that "everything" is under Judicial review in India, hence S1 is likely true too. For S2, In India, no discretionary power exists for the President unless the Constitution explicitly says so. Since Article 72 has no such exception, the Council’s advice is mandatory. Hence likely false.
UPSC 2025Polity · Parliament
Q67. Consider the following statements: I. On the dissolution of the House of the People, the Speaker shall not vacate his/her office until immediately before the first meeting of the House of the People after the dissolution. II. According to the provisions of the Constitution of India, a Member of the House of the People on being elected as Speaker shall resign from his/her political party Immediately. III. The Speaker of the House of the People may be removed from his/her office by a resolution of the House of the People passed by a majority of all the then Members of the House, provided that no resolution shall be moved unless at least fourteen days’ notice has been given of the intention to move the resolution. Which of the statements given above are correct?
Explanation
Statement 1 is correct: As per Article 94 of the Indian constitution, the Speaker of the House continues in office until the first meeting of the newly constituted Lok Sabha after dissolution.
Statement 2 is incorrect: The Constitution does not mandate the Speaker to resign from their political party. While parliamentary conventions encourage neutrality on part of the Speaker of the House, this is not a constitutional requirement.
Statement 3 is correct: Article 94 of the Indian Constitution addresses the process for removing the Speaker of the Lok Sabha. It states that the Speaker may be removed through a resolution supported by a majority of the current members of the House, provided that at least 14 days’ notice is given before moving the resolution.
Exam tip:
For S2,"According to the provisions of the Constitution..." This is a strong claim. Any such rule must be explicitly stated in the text of the Constitution, not by convention or practice. Multiple real-life examples--like Om Birla and Sumitra Mahajan--prove that Speakers have continued as party members during their tenure. Also, it uses strong absolute language: "shall resign... immediately" and attributes it to the Constitution -- this makes it factually and logically incorrect. Giving option C as correct.
UPSC 2025Polity · Parliament
Q68. Consider the following statements: I. If any question arises as to whether a Member of the House of the People has become subject to disqualification under the 10th Schedule, the President’s decision in accordance with the opinion of the Council of Union Ministers shall be final. II. There is no mention of the word ‘political party’ in the Constitution of India. Which of the statements given above is/are correct?
Explanation
Statement 1 is incorrect: Under the Tenth Schedule (anti-defection law), the authority to decide on disqualification due to defection is the Speaker of the House of the People (Lok Sabha), not the President. The Speaker’s decision is final in cases of anti-defection.
Statement 2 is incorrect: The 52nd Amendment, enacted in 1985, added the Tenth Schedule to the Indian Constitution. This amendment introduced the term ‘Political Party’ into the Constitution for the first time.
Additional insight:
The President’s role in disqualification is limited to other grounds under Article 102, and even then, the President must act according to the opinion of the Election Commission, not the Council of Ministers. Article 102 of the Indian Constitution lays down the grounds for disqualification of a person from being chosen as, or for being, a member of either House of Parliament (Lok Sabha or Rajya Sabha). The main grounds include:
Holding any office of profit under the Government of India or a State (unless exempted by Parliament). Being of unsound mind, as declared by a competent court. Being an undischarged insolvent. Not being a citizen of India, or voluntarily acquiring citizenship of a foreign state, or acknowledging allegiance to a foreign state. Being disqualified by or under any law made by Parliament.
UPSC 2025Indian Economy · Industry
Q69. Consider the following statements: Statement I: In India, State Governments have no power for making rules for grant of concessions in respect of extraction of minor minerals even though such minerals are located in their territories. Statement II: In India, the Central Government has the power to notify minor minerals under the relevant law. Which one of the following is correct in respect of the above statements?
Explanation
Statement 1 is incorrect: Under Section 15 of the Mines and Minerals (Development and Regulation) Act, 1957 (MMDR Act), State Governments do have the power to make rules for regulating the grant of mineral concessions in respect of minor minerals within their territories. This includes framing rules for mining leases, quarry leases, and other concessions.
Statement 2 is correct: The Central Government has the authority to declare a mineral as a ‘minor mineral’ by notification in the Official Gazette as per Section 3(e) of the Mines and Minerals (Development and Regulation) Act, 1957 (MMDR Act).
Exam tip:
For S1, The phrase "minor minerals" naturally implies decentralization. It’s intuitive: minor = local = state-level control. Also, The S1 uses "have no power", which is absolute. In UPSC questions, such absolutes are usually a red flag, unless the Constitution or statute explicitly says so (which is not the case here). Giving option D as correct.
UPSC 2025Environment and Ecology · Environmental Laws, Conventions and Policies
Q70. Which organization has enacted the Nature Restoration Law (NRL) to tackle climate change and biodiversity loss?
Explanation
The European Union has introduced the Nature Restoration Law (NRL) to address climate change and the loss of biodiversity. This law requires member countries to meet specific targets for restoring damaged ecosystems on both land and sea, forming a central part of the EU’s environmental strategy. Its goal is to rejuvenate nature throughout Europe, benefiting wildlife, the climate, and communities. If properly enforced, the law could have a transformative impact. It is now essential for both the European Parliament and EU member nations to approve and promptly implement the legislation.
Exam tip:
The word "enacted" implies legislative authority -- only bodies with law-making power can do this. Only the EU has the jurisdiction and institutional setup to actually enact a law like the Nature Restoration Law (NRL).
Answer key for these questions
Q
UPSC year
Correct answer
61
2025
(a) Both Statement I and Statement II are correct and Statement II explains Statement I
62
2025
(a) I and II only
63
2025
(c) All the three
64
2025
(b) Only two
65
2025
(a) silver iodide and potassium iodide
66
2025
(a) I only
67
2025
(c) I and III only
68
2025
(d) Neither I nor II
69
2025
(d) Statement I is not correct but Statement II is correct
70
2025
(a) The European Union
Frequently asked questions
How many previous year UPSC questions are there on all subjects?
This page covers 99 previous year UPSC Prelims GS Paper-I questions on the UPSC 2025 Prelims, asked from 1995 to 2025. Each has the correct answer and an explanation.
How should I use previous year UPSC questions for Prelims?
Attempt each question first, then open the answer and read the explanation for every option. Repeat by chapter, and track which statements UPSC reuses across years. Previous year questions show the exam pattern and difficulty level.
Which years are covered for all subjects?
Questions on the UPSC 2025 Prelims are available for 31 years, from 1995 to 2025. Use the Year filter to practise a single paper.
