UPSC CSE Mains 2025 Revision Checklist: Top 15 Environment and Geography topics aspirants shouldn't miss

Indian Express

8 hours ago

Are You Mains Ready? With the UPSC CSE Mains 2025 beginning on August 22, no subject can be taken for granted—each one has the potential to surprise you with unexpected questions. Thus, to make your environment and geography preparation sharper and more focused, here's a checklist of important topics with PYQ insights based on the syllabus of General Studies, highlighting why the given topic is relevant. Are these topics part of your final revision plan yet?
📌 Why in News?
On August 5, a sudden flash flood caused by a cloudburst in the Kheer Ganga river catchment area swept away houses, shops and roads, leaving a trail of destruction. This latest incident adds to a growing list of extreme weather events that have struck the hill state in recent years, particularly during the monsoon.
In 2022, UPSC has asked a question: Explain the mechanism and occurrence of cloudbursts in the context of the Indian subcontinent. Discuss two recent examples. Questions related to climate events and climate-related reports have been UPSC favourites. In this regard, having a comprehensive understanding of this topic is important from the exam perspective.
Key dimensions to cover:
— What are cloudbursts? Is the frequency of cloudbursts increasing?
— Can cloudbursts be forecast?
— What is the Glacial Lake Outburst Flood (GLOF)?
— Why do cloudbursts mostly occur in hilly or mountainous areas, and how can they lead to flash floods?
— How can cloudbursts lead to flash floods?
— What should India do to reduce the risk of future catastrophe?
PYQ Insight:
📍What is the phenomenon of 'Cloudbursts'? Explain. ( UPSC CSE 2024)
Other important article covering the same topic
UPSC Issue at a Glance | Uttarkashi Cloudburst: What UPSC aspirants must-know for Prelims and Mains
📌 Why in News?
The deadliest flash floods in Spain's modern history claimed more than 200 lives. The disaster became Europe's worst flood-related tragedy since 1967, when at least 500 people died in Portugal. India is also highly vulnerable to floods. Floods are a recurrent phenomenon, which cause huge loss of lives and damage to livelihood systems, property, infrastructure and public utilities. In the last few years, the frequency of flash floods has increased. Thus, it becomes important to understand this topic for mains.
Key dimensions to cover:
— Driving factors of flash floods
— Role of climate change in flash floods
— How the escalating hazard of flash floods in India due to climate change.
— Measures to prevent disruptions by flood and extreme weather events.
— Significance of Interlinking of rivers
— Government's initiatives to counter the problem of floods
PYQ Insight:
📍The interlinking of rivers can provide viable solutions to the multi-dimensional inter-related problems of droughts, floods, and interrupted navigation. Critically examine. (UPSC CSE 2020)
Other important article covering the same topic
How flash floods are affecting India
What are flash floods and why they may increase in the next few years
How to prevent disruptions by flood?
📌 Why in News?
The COP29 outcomes disappointed developing economies, which severely undermined the objectives of the Paris Agreement by promising just $300 billion in climate finance, instead of the projected requirement of more than $1 trillion a year. India has consistently stressed the need for adequate financial support from developed nations to help developing countries meet their climate commitments. In this context, it is important to understand the outcomes of COP 29 from a broader perspective for mains.
Key dimensions to cover:
— What does climate finance mean?
— India's climate commitments.
— Budgetary allocations and schemes for climate action
— What are the implications of inadequate climate finance for India and other developing nations in meeting their climate goals?
— How does India's focus on adaptation strategies differ from its mitigation efforts, and why is this shift important?
— How has India's approach to climate governance evolved from 'initial reluctance' to becoming a 'responsible climate leader'?
— In what ways has India balanced its developmental priorities with its commitments to global climate governance over the years?
PYQ Insight:
📍Describe the major outcomes of the 26th session of the Conference of the Parties (COP) to the United Nations Framework Convention on Climate Change (UNFCCC). What are the commitments made by India in this conference? (UPSC CSE 2021)
Other important article covering the same topic
How COP29 outcomes compel countries like India to reassess their climate targets
COP29: How India plays a pivotal role in global climate governance
Understanding the impacts of climate change and the path to effective adaptation
📌 Why in News?
The standing committee of the National Board for Wildlife (SC-NBWL), has decided to revisit the government's 2011 guidelines on declaration of eco-sensitive zones (ESZ) around national parks and wildlife sanctuaries to make them more site-specific and tuned to ecological and socio-economic realities of each region, as per the minutes of its June 26 meeting.
Key dimensions to cover:
— What are eco-sensitive zones (ESZ)? Why are they created?
— What is the significance of ESZs in the context of wildlife conservation in India?
— Know the 2011 guidelines on eco-sensitive zones?
— What is Environmental Impact Assessment (EIA)
— How a blanket 10-km rule for ESZs does not serve the ecological or socio-economic objectives of conservation.
— Challenges faced by states in implementing the ESZ guidelines?
— Implications of ESZ guidelines on local communities and development?
PYQ Insight:
📍 'Policy contradictions among various competing sectors and stakeholders have resulted in inadequate 'protection and prevention of degradation' to the environment.' Comment with relevant illustrations. (UPSC CSE 2018)
Other important article covering the same topic
Explained: What are Eco-Sensitive Zones
SC modifies order on eco-sensitive zone around national parks, sanctuaries
Environmental Impact Assessment: Navigating the development-environment dilemma
📌 Why in News?
Plastic pollution has been an important topic for the UPSC exam. The theme of this year's World Environment Day was also #BeatPlasticPollution. The theme aimed to educate people about how plastics are made, used, and disposed of, and the effects they have. Also, in 2022, the United Nations Environment Assembly (UNEA) initiated a process to develop a legally binding treaty on plastic pollution by the end of 2024. In this context, with increased focus on plastic pollution in recent years, it becomes crucial to cover this topic for the exam.
Key dimensions to cover:
— What are the different types of plastic waste?
— Read about plastic pollution and its impact.
— How can the principles of the 3Rs (Reduce, Reuse, Recycle) be effectively implemented in India to combat plastic waste?
— Why is a global plastic treaty required?
— What are the challenges associated with plastic waste management in India?
— What are the measures taken by the Indian government to curb plastic pollution?
(Thought process: Read about the Plastic Waste Management Rules, India Plastics Pact, National Dashboard on Elimination of Single-Use Plastic and Plastic Waste Management, Project REPLAN and other initiatives taken by the government)
PYQ Insight:
📍What are the impediments in disposing the huge quantities of discarded solid waste which are continuously being generated? How do we remove safely the toxic wastes that have been accumulating in our habitable environment? (UPSC CSE 2018)
Other important article covering the same topic
Knowledge Nugget: Plastic Pollution and Global Plastic Treaty — What you need to know for UPSC
How microplastics harm the heart
📌 Why in News?
As India's primary agency responsible for meteorological observations, weather forecasting, and seismology, India Meteorological Department (IMD) celebrates its 150th year of establishment this year. Over its 150 years of existence, the IMD has been vital for disaster preparedness. In this context, its an important topic for mains.
Key dimensions to cover:
— IMD and its expanding role.
— Functions of IMD
— Key initiatives for enhancing accuracy of forecasts
— How the evolution of the IMD over 150 years reflects India's changing priorities in science, governance, and disaster management.
— How does the role of IMD as a regional node of the World Meteorological Organization (WMO) enhance India's global standing in climate governance and disaster risk reduction?
— What are the key infrastructural and technological gaps that still limit the IMD's ability to deliver accurate and localized forecasts, particularly in rural and remote areas?
Other important article covering the same topic
How IMD became central to India's climate and disaster preparedness
📌 Why in News?
Glaciers play a vital role in regulating the Earth's climate and providing fresh water to billions of people worldwide. To raise awareness about the significance of preserving glacier health in a warming world, the United Nations has declared 2025 as the International Year of Glaciers' Preservation. Furthermore, starting from 2025, March 21 will be marked annually as the World Day of Glaciers. This initiative was proposed by Tajikistan during the first meeting of the Water and Climate Leaders in their Call for Action on March 3, 2021, and was subsequently adopted by the UN General Assembly in December 2022. In this context,
Key dimensions to cover:
— Why is the Hindu Kush Himalaya (HKH) region referred to as the 'Third Pole of the World'?
— What makes the region a crucial 'freshwater tower' for South Asia?
— What are the potential long-term impacts of continued warming on water availability and agricultural productivity in the Himalayas?
— What is the significance of the United Nations declaring 2025 as the International Year of Glaciers' Preservation?
— What are the risks associated with expanding glacial lakes, and how do they affect downstream communities and infrastructure?
— What are the goals of the National Mission for Sustaining the Himalayan Ecosystem (NMSHE) under India's National Action Plan on Climate Change (NAPCC)?
Other important article covering the same topic
UN urges to save glaciers, secure the planet
Hindu Kush Himalaya faces increased risks amid record glacier melting
Water and climate security at risk due to low snow levels in Hindu Kush region
📌 Why in News?
Key dimensions to cover:
— What are heatwaves and the criteria for declaring them?
— What causes heatwaves?
— What are heatwave conditions in India?
— What are the impacts of heatwaves?
— What measures should be taken to mitigate the impacts of heatwaves?
— What is the difference between a heatwave and a warm spell?
— Why is humidity an important aspect when measuring heat exposure?
PYQ Insight:
📍 Bring out the causes for the formation of heat islands in the urban habitat of the world. (UPSC CSE 2013)
Other important article covering the same topic
UPSC Issue at a Glance | Heatwaves: 5 Key Questions You Must Know for Prelims and Mains
Five things India needs to do to combat heatwave
📌 Why in News?
Not only in India but around the world, the frequency of landslides has increased. The increased frequency and large-scale hazards associated with landslides have made them one of the most significant natural disasters for mankind. Thus, it is important to have a broad understanding of landslides so that we can manage such natural disasters more effectively.
Key dimensions to cover:
— What are landslides? What causes landslides?
— How are landslides classified? How prone is India to landslides?
— Differentiate the causes of landslides in the Himalayan region and Western Ghats.
— What is the significance of environment impact assessment in managing landslides?
— What is the Sendai Framework for Disaster Risk Reduction?
— What are the recommendations of the Gadgil and Kasturirangan committee?
— What measures should be taken for the efficient management of landslides?
— What measures have been taken by the Government to reduce the damage caused by landslides?
PYQ Insight:
📍Describe the various causes and the effects of landslides. Mention the important components of the National Landslide Risk Management Strategy. (UPSC CSE 2021)
The Himalayas are highly prone to landslides.' Discuss the causes and suggest suitable measures of mitigation. (UPSC CSE2016)
Other important article covering the same topic
UPSC Issue at a Glance | Landslides : 5 Key Questions You Must Know for Prelims and Mains
📌 Why in News?
The World Environment Day 2024 focused on land restoration, desertification, and drought resilience. Land restoration also plays a vital role in the UN Decade on Ecosystem Restoration (2021-2030) and is essential for achieving the Sustainable Development Goals. In this context, it is important to cover the issue of land degradation and restoration from a broader perspective.
Key dimensions to cover:
— What is land degradation?
— What are the causes of land degradation and desertification?
— What are the impacts of land degradation and desertification?
— Why is land restoration significant?
— What initiatives have been taken globally and nationally to combat land degradation?
— What measures should be taken to promote afforestation and combat desertification?
PYQ Insight:
📍The process of desertification does not have climate boundaries. Justify with examples. (UPSC CSE 2020)
📍In what way micro-watershed development projects help in water conservation in drought-prone and semi-arid regions of India? (UPSC CSE 2016)
Other important article covering the same topic
UPSC Issue at a Glance | Land Degradation and Restoration: 5 Key Questions You Must Know for Prelims and Mains
How India pushes for ecological restoration
📌 Why in News?
The California Los Angeles Wildfires in January put hundreds of thousands under evacuation orders and charred more than 40,000 acres of land. With climate change, wildfires are becoming a major environmental challenge. Thus, covering the topic of wildfires through linking the environment, climate change, disaster management, and biodiversity becomes crucial.
Key dimensions to cover:
— Three different classes of wildland fires
— What are the causes of the wildfires occurring in Southern California?
— How frequent are forest fires in India?
— What are the factors behind the forest fires in India?
— How far anthropogenic activities are responsible for forest fires?
— What impacts do wildfires have?
— What measures can be taken to mitigate and manage wildfires?
Other important article covering the same topic
UPSC Issue at a Glance | What to know about Wildfires: 4 key questions answered for your UPSC Exams
📌 Why in News?
Cities in India and outside the country often experience poor air quality. Also, the issue of air pollution is significant for the UPSC CSE, as environmental pollution is explicitly mentioned in the General Studies Paper III syllabus. The UPSC has previously asked questions related to air quality. Additionally, this topic is relevant for essay writing. In this context, it is essential to understand the issue of air pollution from a broader perspective.
Key dimensions to cover:
— Air pollution and its sources.
— What impact does air pollution have on health, the economy, and the environment in India? — What are the government initiatives and programs for combating air pollution in India?
— What steps should be taken to control air pollution?
— National Clean Air Programme and Graded Response Action Plan.
— Artificial rain (cloud seeding)
PYQ Insight:
📍Describe the key points of the revised Global Air Quality Guidelines (AQGs) recently released by the World Health Organisation (WHO). How are these different from its last update in 2005? What changes in India's National Clean Air Programme are required to achieve revised standards? (UPSC CSE 2021)
Other important article covering the same topic
UPSC Issue at a Glance | Air Pollution: 4 Key Questions You Must Know for Prelims and Mains
Why air pollution should be an urgent national priority
📌Why in News?
A tsunami is a series of giant ocean waves caused by earthquakes or volcanic eruptions under the ocean. December 26, 2024, marked the 20 years of the 2004 tsunami when a magnitude 9.1 earthquake triggered a tsunami that devastated 14 countries, killing over 227,000 people. Survivors battled immense loss, trauma, and economic hardship. Two decades later, advances in warning systems and preparedness reflect hard lessons learnt from one of the deadliest natural disasters in history. In this context, it becomes important to cover this topic for the mains exam.
Key dimensions to cover:
— What is a tsunami, and how is it formed?
— How does an earthquake lead to a tsunami?
— Discuss the geological and seismic factors responsible for the generation of tsunamis.
— What are the key differences between a tsunami and regular ocean waves?
— Which regions of India are most vulnerable to tsunamis?
— What initiatives has the government undertaken to address tsunami-related disaster management?
— Map Work: Tsunami-prone areas in India and in the World
PYQ Insight:
📍On December 2004, tsunami brought havoc on fourteen countries including India. Discuss the factors responsible for the occurrence of tsunami and its effects on life and economy. In the light of guidelines of NDMA (2010) describe the mechanisms for preparedness to reduce the risk during such events. (UPSC CSE 2017)
Other important article covering the same topic
How the 2004 tsunami changed early warning systemsKnowledge as a shield
Japan earthquake triggers tsunami warning: What is a tsunami, why does it keep forming in the island country?
📌Why in News?
Mangroves have been the focus of conservationists for years, and it is difficult to overstate their importance in the global climate context. Recently, on July 26 the International Day for the Conservation of the Mangrove Ecosystem was celebrated. It is an important step towards spreading awareness about mangroves and their conservation. In this context, covering this topic from a broader perspective becomes essential.
Key dimensions to cover:
— What are mangroves and where are they found in India?
— What are the multifaceted significance of mangroves?
— What are the threats faced by mangrove forests in India?
— What steps have been taken for mangrove conservation?
PYQ Insight:
📍Discuss the causes of depletion of mangroves and explain their importance in maintaining coastal ecology. (UPSC CSE 2019)
Other important article covering the same topic
UPSC Issue at a Glance | Mangroves in focus: Understanding significance, threats and conservation
📌 Why in News?
As part of a global initiative to switch to renewable energy sources and reduce fossil fuel consumption, attention has increasingly been focussed on biofuel production, wherein bioethanol has emerged as a promising alternative.
Key dimensions to cover:
— How do the three categories of biomass fuels – thermochemical, biochemical, and agrochemical – differ in terms of efficiency and environmental impact?
— Importance of Biofuels
— India's Progress on the Path of Sustainable Energy through Biofuels
— Issues and Challenges Related to Biofuels
— Government Initiatives and Policies on Biofuels
— Could an overreliance on biomass energy create new environmental challenges? If so, what might they be?
PYQ Insight:
📍'Access to affordable, reliable, sustainable and modern energy is the sine qua non to achieve Sustainable Development Goals (SDGs)'.Comment on the progress made in India in this regard. (UPSC CSE 2018)
Other important article covering the same topic
Can biofuel really replace fossil fuels?
World Biofuel Day – All you need to know for UPSC Prelims and Mains
How India's biofuel potential complements its leadership in sustainable aviation fuel
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