Environment & Ecology has emerged as one of the most high-scoring and trend-driven sections of the UPSC Civil Services Preliminary Examination. Over the last decade, UPSC has consistently asked 15–20 questions from this area, often blending static concepts with current environmental issues.
For UPSC Prelims 2026, aspirants must focus on core ecology concepts, biodiversity, environmental laws, climate change frameworks, and international conventions, along with strong current-affairs integration. This article provides a comprehensive, exam-oriented guide to the high-scoring areas in Environment & Ecology, along with a smart preparation strategy and FAQs.
Why Environment & Ecology is a High-Scoring Section in Prelims
Consistently high weightage in Prelims
Questions are largely static + current-based, not opinion-driven
Strong overlap with Geography, Science & Current Affairs
Conceptual clarity leads to easy elimination in MCQs
👉 With focused preparation, Environment can become a sure-shot scoring area.
PART I: CORE ECOLOGY CONCEPTS (MUST-KNOW)
1. Ecosystem & Its Components
UPSC frequently tests basic ecological understanding.
Key concepts:
Biotic and abiotic components
Producers, consumers, decomposers
Food chain and food web
Ecological pyramids (number, biomass, energy)
Energy flow (10% law)
2. Biogeochemical Cycles
Carbon cycle
Nitrogen cycle
Phosphorus cycle
Water (hydrological) cycle
👉 Questions often focus on human intervention and climate impact.
3. Ecological Succession & Biomes
Primary vs secondary succession
Climax community
Major biomes: tundra, taiga, grasslands, deserts, tropical forests
PART II: BIODIVERSITY & CONSERVATION (VERY HIGH WEIGHTAGE)
4. Biodiversity: Levels & Importance
Genetic, species, ecosystem diversity
Keystone species
Endemic species
Flagship, umbrella, and indicator species
5. Biodiversity Hotspots
Concept by Norman Myers
Criteria for hotspot identification
Indian hotspots:
Himalayas
Indo-Burma
Western Ghats–Sri Lanka
Sundaland (Nicobar Islands)
6. Protected Areas in India
Highly favourite area for UPSC.
National Parks
Wildlife Sanctuaries
Biosphere Reserves
Conservation Reserves & Community Reserves
👉 Focus on differences, legal status, and recent additions.
7. Species in News
IUCN Red List categories
Critically Endangered, Endangered, Vulnerable species
Important fauna & flora in news
Invasive alien species
PART III: ENVIRONMENTAL POLLUTION & CLIMATE CHANGE
8. Environmental Pollution
Air pollution (PM2.5, PM10)
Water pollution (BOD, COD)
Soil pollution
Noise pollution
Eutrophication
9. Climate Change
One of the most repeatedly tested themes.
Key topics:
Greenhouse effect & global warming
Greenhouse gases
Climate feedback mechanisms
Carbon sequestration
Mitigation vs adaptation
10. International Climate Agreements
UNFCCC
Kyoto Protocol
Paris Agreement
Nationally Determined Contributions (NDCs)
IPCC reports
👉 India’s climate commitments are highly important.
PART IV: ENVIRONMENTAL LAWS, INSTITUTIONS & GOVERNANCE
11. Environmental Laws in India
UPSC often asks statement-based questions.
Important Acts:
Environment Protection Act, 1986
Wildlife Protection Act, 1972
Forest Conservation Act, 1980
Biological Diversity Act, 2002
National Green Tribunal Act, 2010
12. Environmental Institutions
Ministry of Environment, Forest and Climate Change (MoEFCC)
National Biodiversity Authority (NBA)
Central & State Pollution Control Boards
National Green Tribunal (NGT)
PART V: CURRENT ENVIRONMENTAL ISSUES (PRELIMS GOLDMINE)
13. Environmental Conventions & Protocols
Ramsar Convention
CITES
Convention on Biological Diversity (CBD)
Basel, Rotterdam & Stockholm Conventions
Montreal Protocol
14. Government Initiatives & Schemes
National Action Plan on Climate Change (NAPCC)
National Afforestation Programme
CAMPA
Project Tiger & Project Elephant
Mission LiFE
Smart Strategy to Prepare Environment & Ecology for Prelims 2026
Build strong static foundation in ecology
Integrate static topics with current environmental news
Revise protected areas and species regularly
Solve previous year questions (PYQs) thoroughly
Use maps for national parks & biosphere reserves
Common Mistakes to Avoid
Studying Environment without basics of ecology
Ignoring international conventions
Memorising species without understanding habitat
Skipping revision due to vastness
Conclusion
Environment & Ecology is a decisive section for clearing UPSC Prelims 2026. Its predictable nature, combined with current relevance, makes it a high-scoring subject if prepared strategically. Aspirants who master ecology fundamentals and link them with environmental governance and current affairs can gain a significant edge over others.
Frequently Asked Questions (FAQs)
Q1. How many questions are asked from Environment in Prelims?
Usually 15–20 questions every year.
Q2. Is Environment & Ecology purely current-affairs based?
No. It is a mix of static ecology concepts and current developments.
Q3. Are international environmental conventions important?
Yes. UPSC frequently asks questions from global environmental agreements.
Q4. Should I memorise all species for Prelims?
Focus on species in news and their habitat, not all species.
Q5. Is Environment useful for Mains as well?
Yes. It overlaps with GS Paper III and Essay topics.
