Science and Technology PYQs for UPSC Prelims: Weightage and Themes
Science and technology is 13% of the Prelims paper, and biotechnology alone is a fifth of it. The 2026 paper asked 20 — the highest in fourteen years.
Science and technology is the subject non-science graduates dread and science graduates over-estimate their advantage in. Both reactions misread what is being asked.
Across 183 questions between 2013 and 2026 — 13% of the paper, the fourth-largest subject — the examiner is not testing whether you can do science. He is testing whether you understand what a technology is, what it does, and why it was in the news. A biology graduate has an edge on the mechanism questions and none at all on the applications ones.
The Numbers
| Year | 2013 | 2014 | 2015 | 2016 | 2017 | 2018 | 2019 | 2020 | 2021 | 2022 | 2023 | 2024 | 2025 | 2026 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Questions | 16 | 11 | 10 | 14 | 10 | 12 | 15 | 13 | 13 | 15 | 10 | 11 | 13 | 20 |
An average of 13.1 a year, and the most stable subject in the paper — a standard deviation of 2.7, the lowest of any subject, with a range of just 10 to 20.
That stability is worth noticing. Where polity can swing from 5 to 22 and geography from 4 to 20, science and technology has never once dipped into single figures. It is the most plannable block in Prelims.
The 2026 paper asked 20, the highest in the fourteen-year run.
Where the 183 Questions Sit
| Topic | Questions | Share |
|---|---|---|
| Biotechnology | 37 | 20.2% |
| Emerging Technologies | 28 | 15.3% |
| Life Sciences | 26 | 14.2% |
| Core Concepts and Foundational Science | 20 | 10.9% |
| Information and Communication Technology | 13 | 7.1% |
| Space Technology | 12 | 6.6% |
| Defence Technology | 10 | 5.5% |
| Science and Technology | 9 | 4.9% |
| Energy and Clean Technology | 7 | 3.8% |
| General Science in Everyday Life | 4 | 2.2% |
| Science and Technology Policy, IPR, and Achievements | 4 | 2.2% |
| Monetary Policy | 3 | 1.6% |
| Capital Market | 3 | 1.6% |
| Agriculture and Crops | 3 | 1.6% |
| Minerals and Energy | 1 | 0.5% |
| Banking and Financial System | 1 | 0.5% |
| Prime Minister and Cabinet | 1 | 0.5% |
| Rivers and Drainage | 1 | 0.5% |
Three topics — biotechnology, emerging technologies and life sciences — carry 91 of 183 questions. That is half the subject in three blocks.
Biotechnology Is the Largest Topic by Far
Thirty-seven questions, a fifth of the subject, and comfortably ahead of everything else.
What recurs:
- Gene editing and its tools — CRISPR and its variants, gene therapy, genetically modified organisms and the regulatory framework around them
- Vaccines and their platforms — the difference between inactivated, viral-vector, mRNA and subunit approaches
- Diagnostics — PCR and its variants, antigen and antibody testing, biosensors
- Applications in agriculture — Bt technology, biofortification, tissue culture
- Regulatory and ethical structures — GEAC, biosafety levels, the Cartagena Protocol
The pattern is consistent: a technology in the news, asked as “what does it actually do.” Someone who read a news item about a gene-edited crop and stopped there will fail these; someone who spent ten minutes understanding the underlying technique will pass them for years, because the technique does not change.
Emerging Technologies and ICT
Emerging technologies (28) plus information and communication technology (13) make 41 questions.
Artificial intelligence and machine learning, blockchain and distributed ledgers, quantum computing and communication, 5G, the Internet of Things, semiconductors, additive manufacturing, and drones. On the ICT side: network technologies, cybersecurity concepts, and digital public infrastructure.
These are the most current-affairs-driven questions in the subject and the ones that most reward reading science journalism rather than textbooks.
Life Sciences and Foundational Science
Life sciences (26) plus core concepts and foundational science (20) come to 46 questions — a quarter of the subject.
This is the closest the paper comes to school science: human physiology, disease and immunity, cell biology, basic chemistry of materials, and the physics behind everyday phenomena. It is also the block where the NCERTs genuinely help. Class 9 to 12 science covers most of this ground, and for a non-science graduate it is the highest-return reading available in the subject.
Space and Defence
Space technology (12) plus defence technology (10) make 22 questions.
Space questions cluster on ISRO missions and their objectives, orbit types and what each is used for, launch vehicle classes, and international missions in the news. Defence covers missile classes and their ranges, aircraft and naval platforms, and indigenous development programmes.
Both are essentially current-affairs blocks attached to a small stable core of concepts — what a geostationary orbit is, what a cruise missile is — that is worth learning once.
How to Prepare This Subject
Read for what a technology does, not that it exists. Nearly every question in the current-affairs half rewards one level of understanding below the headline.
Non-science graduates: do the NCERTs. Classes 9 to 12 science underwrite 46 questions of life sciences and foundational concepts, and nothing else covers that ground as efficiently.
Science graduates: do not coast. Your degree helps with roughly a quarter of the subject. Emerging technologies, space and defence are current affairs and reward nobody’s undergraduate training.
Keep a running technology list. One line per technology that appeared in the year’s news: what it is, what it does, who runs it, why it was in the news. This is the single most useful artefact for this subject.
Trust the stability. At a standard deviation of 2.7, this subject is the safest place to invest preparation time in the whole paper.
For the full paper-level picture, see UPSC Prelims PYQ Topic-wise. Our Science & Technology hub has the topic notes, and you can practise these questions at Practice.
Frequently Asked Questions
How many science and technology questions come in UPSC Prelims? An average of 13.1 a year — 183 questions across the 2013 to 2026 papers, or 13% of the paper. The range is 10 to 20, the narrowest of any subject.
Which science and technology topic is asked most in UPSC Prelims? Biotechnology, with 37 questions — a fifth of the subject. Emerging technologies (28) and life sciences (26) follow.
Do I need a science background for UPSC Prelims? No. Roughly a quarter of the subject is foundational science that the school NCERTs cover; the rest is applications and current affairs, where a science degree confers little advantage.
Which NCERTs should I read for science and technology? Classes 9 to 12 science, read once for the concepts rather than the problems. They underwrite the life-sciences and foundational-science blocks, which together are 46 questions.
Is science and technology weightage rising? Slightly — 12.6 questions a year in 2013-2019 against 13.6 in 2020-2026. The 2026 paper’s 20 questions is the highest single-year count in the fourteen-year run.