The UPSC Prelims 2025 question paper continued its legacy of being unpredictable, analytical, and concept-driven. With 100 questions in General Studies Paper I, the trend clearly reflected a balanced distribution across subjects like Polity, Economy, Environment, Science & Tech, History, and Geography. Among them, Environment & Ecology stood out with a total of 13 questions, constituting a significant portion and demanding focused preparation.
Overall Nature of UPSC Prelims 2025
This year, the paper appeared moderately tougher compared to the previous year. Questions across all subjects ranged from easy to medium and difficult levels, indicating a layered testing approach. The hallmark of this year's paper was its emphasis on core fundamentals, often intertwined with current affairs, reinforcing the need for integrated preparation.
Given below is the breakdown of the 100 questions asked in CSE Prelims 2025.
Environment & Ecology Section: Key Observations
The Environment & Ecology section in UPSC Prelims 2025 reflected a noticeable shift in focus. Rather than concentrating on static topics like species and ecological behavior, the paper leaned towards contemporary environmental issues and technological solutions. The questions tested both core concepts and awareness of current global challenges, particularly those linked to climate change and innovation.
Notable Themes Covered:
- Climate Change Mitigation Technologies – e.g., Direct Air Capture
- Artificial Weather Modification – e.g., Artificial Rainfall
- Sustainable Development and Climate Finance Mechanisms-e.g. Article 6 Paris Climate deal
The Detailed Analysis of UPSC Prelims 2025 Environment Section are as follows:
UPSC Prelims Environment & Ecology Q.
Consider the following statements:
I. Carbon dioxide (CO2) emissions in India are less than 0.5 t CO2/ capita.
II. In terms of CO2 emissions from fuel combustion, India ranks second in Asia-Pacific region.
III. Electricity and heat producers are the largest source of CO2 emissions in India.
Which of the statements given above is/are correct?
(a) I and III only
(b) II only
(c) II and III only
(d) I, II and III
Answer: C
Explanation
- In 2022, India's per capita CO2 emissions rose to 2 tonnes, representing a 5% increase, but remained less than half the global average. The United States topped the per capita emissions chart with 14.9 tonnes, followed by Russia (11.4), Japan (8.5), China (8), and the European Union (6.2), according to the Global Carbon Project. The global average was 4.7 tonnes. Hence, statement I is not correct.
- In terms of CO2 emissions from fuel combustion, India ranks second in Asia-Pacific region. Hence, statement II is correct.
- Electricity and heat producers are the largest source of CO2 emissions in India. Hence, statement III is correct.
MOTIVATION, SOURCES AND COVERAGE OF PRELIMS QUESTION IN THE VISIONIAS SOURCES
Motivation: India's carbon emissions are frequently discussed in the news.
Sources:
UPSC Prelims Environment & Ecology Q.
With reference to the planet Earth, consider the following statements:
I. Rain forests produce more oxygen than that produced by oceans.
II. Marine phytoplankton and photo-synthetic bacteria produce about 50% of world's oxygen.
III. Well-oxygenated surface water contains several folds higher oxygen than that in atmospheric air.
Which of the statements given above is/are correct?
(a) I and II
(b) II only
(c) I and III
(d) None of the above statements is correct
Answer: B
Explanation
- Scientists estimate that roughly half of the oxygen production on Earth comes from the ocean. The majority of this production is from oceanic plankton — drifting plants, algae, and some bacteria that can photosynthesize. One particular species, Prochlorococcus, is the smallest photosynthetic organism on Earth. But this little bacteria produces up to 20% of the oxygen in our entire biosphere. That’s a higher percentage than all of the tropical rainforests on land combined. Hence, statement I is not correct.
- More than half of the oxygen we breathe comes from marine photosynthesizers, like phytoplankton and seaweed. Both use carbon dioxide, water and energy from the sun to make food for themselves, releasing oxygen in the process. Hence, statement II is correct.
- Oxygen content is highest at the surface. As depth increases, dissolved oxygen declines, reaching a minimum between a few hundred meters and 1000 m deep, the aptly-named oxygen minimum layer. It should be noted that even though dissolved oxygen is highest at the surface, there is still far less oxygen in the water than is found in the air. Well-oxygenated surface water may only contain around 8 mg O2/l, while the air contains 210 mg O2/l. Hence, statement III is not correct.
MOTIVATION, SOURCES AND COVERAGE OF PRELIMS QUESTION IN THE VISIONIAS SOURCES
Motivation:To Test understanding of Earth's oxygen cycle, highlighting marine contribution.
Sources:
- https://oceanservice.noaa.gov/facts/ocean-oxygen.html
- https://ocean.si.edu/ocean-life/plankton/every-breath-you-take-thank-ocean#:~:text=That's%20right%E2%80%94more%20than%20half,do%20it%20in%20the%20ocean.
UPSC Prelims Environment & Ecology Q.
Consider the following statements:
Statement I: Circular economy reduces the emissions of greenhouse gases.
Statement II: Circular economy reduces the use of raw materials as inputs.
Statement III: Circular economy reduces wastage in the production process.
Which one of the following is correct in respect of the above statements?
(a) Both Statement II and Statement III are correct and both of them explain Statement I
(b) Both Statement II and Statement III are correct but only one of them explains Statement I
(c) Only one of the Statements II and III is correct and that explains Statement I
(d) Neither Statement II nor Statement III is correct
Answer: A
Explanation
- Circular economy strategies (like recycling, reuse, repair) reduce emissions by lowering energy use and avoiding emissions from raw material extraction and waste management. Statement I is correct.
- A key aim of the circular economy is to retain the value of products and materials in use for as long as possible. This key aim would reduce the demand for virgin materials and the GHGs emitted during their extraction and processing. In addition, the energy-intensive parts of the circular economy should be powered by renewable energy.The reuse and recycling of materials directly cut down the need for virgin/raw materials. Statement II is correct.
- Circular models aim to design out waste, improving efficiency. Statement III is correct.
MOTIVATION, SOURCES AND COVERAGE OF PRELIMS QUESTION IN THE VISIONIAS SOURCES
Motivation: Circular Economy is a term often seen in the news.
Sources:
Coverage of the topic in the VisionIAS Current Affairs Sources
- PT 365 2025 Update Part 2: Article 3.14.25 Jaipur Declaration on Circular economy
- News today (04 March 2025): Twelfth Regional 3R (Reduce, Reuse, Recycle) and Circular Economy Forum in Asia & the Pacific starts in Jaipur
Coverage of Topic in the VisionIAS All India Test Series/ Sandhan/Open Test
Sandhan Vision IAS Prelims Test Series Initiative
Q. Consider the following statements with respect to the India Plastic Pact, recently in news:
1. It is jointly developed by the World Wide Fund India (WWF) and Confederation of Indian Industries (CII).
2. It aims to promote a circular economy for plastics.
Which of the statements given above is/are correct?
(a) 1 only
(b) 2 only
(c) Both 1 and 2
(d) Neither 1 nor 2
The remaining Environment & Ecology questions from UPSC Prelims 2025 are discussed in - Part 4 of the series.
VisionIAS Faculty Discussion: Environment & Ecology Section Analysis of UPSC Prelims 2025
To help aspirants decode the evolving pattern and approach of UPSC Prelims 2025, our expert faculty at VisionIAS has conducted a detailed analysis session, focusing on the trends, difficulty level, question framing, and effective strategies for future preparation. This video not only breaks down the Environment & Ecology questions but also offers valuable insights on elimination techniques, source mapping, and topic prioritization for UPSC Prelims 2026.
To watch the CSE Prelims 2025 Analysis Video, click on the following link:
UPSC Prelims 2025 | GS Paper 1 | Analysis & Discussion I Geography - Environment
Prepare Smarter with VisionIAS: 10-Year PYQ Environment & Ecology Compilation
To help aspirants systematically decode trends, VisionIAS has released a comprehensive compilation of last 10 years’ Environment & Ecology PYQs (2015–2024). This document offers:
- Topic-wise categorization
- Difficulty level analysis
- Source identification
- Elimination strategies
- Micro-level sub-topic mapping
- Current affairs integration guide
Link to read and download the dcument: 10 year UPSC PYQ Trend Analysis : Environment
Our faculty at VisionIAS has conducted an insightful discussion on the Environment & Ecology PYQ Trend Analysis Document. This session covers key patterns, conceptual depth of questions, and strategies to tackle future Prelims papers more effectively. The discussion also highlights how our 10-year PYQ document can be used as a powerful tool for focused preparation.
To watch the discussion by our faculty, click on the link below: GS Prelims | 10 Year PYQ (2015 - 2024) | Environment - Part 3
Further, understand the UPSC Prelims with VisionIAS's Master Classes on PYQ of UPSC Prelims. This program transforms 13 years of UPSC previous year question papers into a powerful strategy- building resource. Designed to enhance your accuracy, speed, and conceptual clarity, it's a smart way to turn UPSC PYQs into your strongest preparation tool