Science & Technology for UPSC 2026: Complete Notes
7 min read
Feb 20, 2026
Science and Technology is one of the most unpredictable sections in UPSC Prelims and Mains. Between 2015 and 2024, it has contributed anywhere between 4 to 13 questions in Prelims alone — a variance that keeps aspirants guessing every year. Add to this the fact that no single textbook covers it comprehensively, and you have a section that demands a smarter approach than rote learning.
This guide breaks down the entire S&T landscape for UPSC 2026 into structured, exam-relevant notes covering what to study, how to study it, and where the marks actually come from.
Why S&T Demands a Different Strategy
Unlike History or Polity, Science & Technology has no fixed syllabus boundary. The UPSC notification simply says: "Developments and their applications and effects in everyday life." This openness means questions can come from biotechnology, space, defence, IT policy, health tech, or emerging fields like AI and quantum computing.
The good news? The UPSC consistently rewards conceptual clarity over deep technical knowledge. You don't need to understand how a quantum computer works at the physics level you need to understand what it does, why it matters for India, and how it links to policy.
High-Yield Topics for UPSC 2026
1. Space Technology
India's space sector has seen landmark developments that are almost guaranteed to feature in exams.
- ISRO missions: Chandrayaan-3 (soft landing on Moon's south pole), Aditya-L1 (solar observation), Gaganyaan (India's first crewed mission timeline and objectives are exam-ready facts)
- IN-SPACe and NewSpace India: Understand the policy shift toward private sector participation in space
- Key concepts: Lagrange points, Sun-synchronous orbit, geosynchronous vs. geostationary orbits, cryogenic engines
- Global context: Artemis Accords (India signed in 2023), SpaceX's Starship, ESA missions
2. Biotechnology & Health
This sub-section is high-yield for both Prelims and GS-3 Mains.
- Gene editing: CRISPR-Cas9 mechanism, applications in agriculture and medicine, ethical concerns
- mRNA vaccine technology: How it works, India's indigenously developed vaccines, implications for future pandemics
- Biosafety & GMOs: Bt cotton, GM mustard controversy, regulatory bodies (GEAC, DBT)
- One Health concept: Linkage between human, animal, and environmental health frequently appearing in recent papers
3. Artificial Intelligence & Emerging Tech
AI has gone from a fringe topic to a core UPSC concern in just two years.
- India's AI policy: IndiaAI Mission (₹10,372 crore allocation), National AI Strategy, AI governance frameworks
- Key terminology: Large Language Models (LLMs), generative AI, deepfakes, AI hallucination you should be able to explain these in 2–3 sentences
- Concerns for Mains: Algorithmic bias, AI in warfare (autonomous weapons), data privacy, digital divide
- Semiconductor policy: India Semiconductor Mission, PLI schemes for chip manufacturing critical for GS-3
4. Defence Technology
Questions on defence tech have increased significantly since 2020.
- Missile systems: Agni series, BrahMos (hypersonic variant), DRDO's QRSAM and Astra
- Drone warfare: Swarm drones, Project Cheetah, India's Drone Policy 2021
- Nuclear doctrine: No First Use policy, credible minimum deterrence link with GS-2 international relations
- iDEX (Innovations for Defence Excellence): Startup-driven defence innovation a favourite UPSC angle
5. Quantum Technology
India launched its National Quantum Mission (NQM) in 2023 with a ₹6,003 crore outlay this makes it exam-ready.
- Understand the difference between quantum computing, quantum communication, and quantum sensing
- Quantum Key Distribution (QKD): Unhackable communication practical application and India's progress
- Why it matters: Potential to break existing encryption, drug discovery, logistics optimization
6. Environment-Linked S&T
These topics bridge GS-3's S&T and Environment sections.
- Green hydrogen: National Green Hydrogen Mission, electrolysis process, applications in industry
- Carbon capture technologies: Direct Air Capture, India's commitments under the Paris Agreement
- Nuclear energy: Small Modular Reactors (SMRs), India's three-stage nuclear programme, thorium reserves
How to Approach S&T for Prelims vs. Mains
For Prelims, focus on factual anchors: launch dates, full forms, nodal agencies, and distinguishing features of technologies. A question like "Which of the following correctly describes Quantum Entanglement?" tests conceptual accuracy, not depth.
For Mains (GS-3), the examiner wants you to link technology with policy, society, and governance. A strong answer on AI, for example, would cover its economic potential, risks of misuse, India's regulatory response, and a balanced conclusion. Practise writing 150-word and 250-word answers on at least 8–10 S&T themes before the exam.
Building a Reliable S&T Preparation System
The biggest mistake aspirants make is treating S&T as a last-minute current affairs sprint. Here's a sustainable approach:
- Monthly current affairs: Tag every S&T development with a category (space/biotech/defence etc.) and a one-line significance note
- Source hierarchy: PIB, ISRO/DRDO press releases, and Ministry of Science & Technology announcements are your primary sources not secondary blog summaries
- Revision notes: Maintain a running two-pager per topic that you update every quarter
- Previous year questions (PYQs): Solve the last 10 years of S&T questions thematically patterns repeat in concept, even when the specific tech changes
PrepAiro's AI-powered topic tracker can help you map S&T developments to syllabus areas in real time, so you're never caught off guard by an out-of-left-field question.
Quick Reference: Key Bodies & Initiatives
| Initiative | Nodal Ministry | Key Purpose |
|---|---|---|
| IndiaAI Mission | MeitY | AI infrastructure & skilling |
| National Quantum Mission | DST | Quantum R&D ecosystem |
| India Semiconductor Mission | MeitY | Chip manufacturing PLI |
| IN-SPACe | Dept. of Space | Private space sector regulation |
| National Green Hydrogen Mission | MNRE | Green H₂ production targets |
Final Takeaway
S&T is a section where prepared aspirants consistently outperform self-study candidates not because the content is harder, but because it requires a structured, updated knowledge base that most people build haphazardly. The 2026 exam will almost certainly feature questions on AI governance, space diplomacy, and biotech all three are already embedded in India's current policy landscape.
Treat every technology news item as a potential exam question. Ask yourself: What is it? How does it work in simple terms? Why is India investing in it? What are the risks? Answer those four questions for every major development, and you'll be better prepared than 90% of the field.
