Read This First — How UPSC Tests Science and Technology and How to Crack It

Why Science and Technology Is a High-Return Subject

Welcome to the Science and Technology playlist. Read this first: it explains how UPSC actually tests the subject, so that you spend your time where the marks are. Science and Technology is the one block that rewards understanding how a technology works and then a current development, never one without the other.

Why Science and Technology is a high-return subject

• We analysed 104 Science and Technology questions in the ten Prelims papers of 2015-2024, about 10 a year. The 2025 and 2026 papers brought the block back to a dozen or more, with questions on quantum chips, large language models, drone swarms, stealth and genomics.

• No chapter is huge, but biotechnology and health, information technology, space and everyday science carry most of the weight, and each question usually asks the working principle (what does Cas9 do? what is a qubit?) plus a news hook.

• In Mains GS-III the same material appears as analysis: biotechnology for farmers, space missions, nuclear energy, cyber security, nanotechnology, semiconductors and artificial intelligence.

The Heavy-Topic Map: What to Master First

This table is our count of Science and Technology questions per topic over 2015-2024, with the number in the last three papers (2022-2024) and where the topic sits in this playlist.

The heavy-topic map

How to read the table

• Go deepest on biotechnology, digital technology and space: together they carry about 57 per cent of the questions. Genetic engineering and vaccines alone have produced something almost every year.

• Everyday science is wider than it looks. Pressure cookers, LEDs, plastics, accelerometers and wearables are asked as 'how does this work' questions. Articles 9 to 11 cover the pattern.

• Defence is small but rising. Expect one question a year on missiles, drones or aircraft, increasingly in the 'how many of the above' format.

The 'How Many of the Above' Era

The way questions are asked has changed. This is the most important thing to understand before you start.

The 'How many of the above' era

• Until 2022 direct and simple multi-statement questions dominated. From 2023 more items are 'How many of the above?' or Statement-I/II, and the 2025 and 2026 papers lean on them, so a technology must be understood well enough to judge each statement on its own.

• One planted word ('all types', 'only', a wrong organisation, a reversed pair) makes a statement false. The 2025 UAV question, for example, was built on 'all types of UAVs can do vertical landing'.

• What we do about it. Our practice questions use these formats, and each article ends with a section on how UPSC could ask the topic next.

The Source Set: Currency, Foundation and Official Papers

Science and Technology questions are built from headlines: a satellite launched, a policy notified, a technique that went viral. Three document sets decide most questions.

The source set

• Currency: the PIB year-end reviews of 2025 for the Department of Space, the Department of Science and Technology, the Department of Biotechnology, CSIR, the Department of Atomic Energy, the Ministry of Earth Sciences and the Department of Telecommunications. Every number in the articles is checked against them.

• Foundation: NCERT Science (Classes VI to X) and NCERT Biology Class XII (health, microbes and biotechnology), which supply the principles that UPSC still takes from textbooks.

• Secondary-source flags: where an item rests on a secondary source (the semiconductor project list, the PFBR's status, the DPDP Rules timeline or Mission Drishti), the article says so, so you know what to re-check.

• Official papers: every real PYQ is checked against the official question paper and UPSC's answer key by the printed question number; the explanations are our own. The 2026 key is provisional, and the explanation says so.

How This Playlist Is Organised

The playlist moves from biology to space to digital technology to energy and materials, and ends with a capstone. Go in order, or jump to the heavy topics first.

How the playlist is organised

• Part A, biotechnology and health (Articles 1-4): genetic engineering; reproductive technology, stem cells and genomics; immunity and vaccines; microbes, disease and antimicrobial resistance.

• Part B, space and the universe (Articles 5-6): ISRO, navigation and remote sensing; astronomy and fundamental physics.

• Part C, digital and emerging technology (Articles 7-8): the internet and cyber security; AI, quantum and semiconductors.

• Part D, physics, energy and materials (Articles 9-11): light and communication technologies; energy and nuclear technology; materials, nanotechnology and critical minerals.

• Part E, defence technology (Article 12).

• Part F, capstone (Article 13): the 2025-26 year in numbers. Read it last, or the week before the exam.

• Every article has the same shape: how UPSC asks the topic; the concepts those questions turn on; the 2025-26 developments; How UPSC could ask this next; and Test Yourself with practice questions, real PYQs and, where they exist, the exact Mains questions.

The Study Loop and Science-and-Technology Habits

How you study decides your score as much as what you study. Here is the loop that works for Science and Technology.

The study loop for every topic

1. Read the note end to end. Concentrate on the working principle, then the current development.

2. Solve 'Test Yourself'. Attempt every practice question and real PYQ before tapping 'Show answer'. For each wrong answer, find the statement that tripped you and read the explanation.

3. Write it from memory. Open the recall mode: a few guiding questions appear first. With the note closed, write what you recall and submit.

4. Read your score and breakdown. You see which key points and numbers you covered and which you missed.

5. Revise the gaps, then let the spaced-revision reminders bring the topic back before you forget it.

Science-and-Technology habits

• Ask 'how does it work, what is it used for, who made it?' of every term. Those three questions cover most Prelims items.

• Keep a near-miss list: LTE versus VoLTE, deep learning versus machine learning, ballistic versus cruise, DNA versus RNA viruses, digital signature versus digital certificate.

• Know the agency: ISRO, DRDO, DAE, DBT, CSIR, DST, MeitY, MoES. The cheapest marks are 'which organisation' questions.

• Link every concept to a headline and update your notes on the day a mission launches or a policy is notified.

Do this loop for every article, start with biotechnology, space and digital technology if time is short, and finish with the capstone.