Mains Ready By December. Smash Mains & Smash PYQ Admissions Open
Talk to Mentor

Civilsdaily

GS Paper: GS3-18.Conservation, Environmental Pollution and Degradation, Environmental Impact Assessment.

  • Species in news: Asiatic Wild Dog (Dhole)

    Why in the News?

    The elusive dhole (Cuon alpinus), also known as the Asiatic wild dog, has been rediscovered in Assam’s Kaziranga-Karbi Anglong Landscape (KKAL) after being thought locally extinct.

    About Dhole:

    • Overview: The dhole (Cuon alpinus), also known as the Asiatic wild dog, is a carnivorous mammal from the Canidae family.
    • Habitat: Historically, dholes inhabited southern Russia, Central Asia, South Asia, and Southeast Asia but are now limited to South and Southeast Asia, including India, Nepal, Bhutan, Bangladesh, and China.
    • Clusters in India: In India, dholes are found mainly in the Western and Eastern Ghats, the Central Indian Landscape, and the Northeast.
    • Key States: According to a 2020 study, Karnataka, Maharashtra, and Madhya Pradesh lead in dhole conservation efforts.
    • Social Behaviour: Dholes live in packs of up to 30 but may also hunt solo or in pairs depending on prey availability.
    • Ecological Role: As predators, dholes help regulate prey populations and maintain ecosystem balance.
    • Conservation Status:
      • IUCN Red List: Endangered
      • CITES: Appendix II (not necessarily threatened with extinction but may become so if trade is not closely controlled).
      • Wildlife Protection Act, 1972: Schedule II (considered important for conservation and are granted a high degree of protection).

    Back2Basics: Kaziranga-Karbi Anglong Landscape (KKAL)

    • Geographic Spread: KKAL is located south of the Brahmaputra River in Assam, comprising Kaziranga National Park (KNP) and the Karbi Anglong Hills.
    • Ecological Importance: KNP is a UNESCO World Heritage Site and part of the Indo-Burma Biodiversity Hotspot, known for rich, unmodified ecosystems.
    • Wildlife Corridor: KKAL facilitates seasonal migration during Brahmaputra floods, supporting species movement and survival.
    • Flagship Species: The landscape hosts the world’s largest population of Indian one-horned rhinoceroses, as well as Bengal tigers, elephants, swamp deer, and wild buffalo.
    • B2B Corridor: KKAL forms a vital link in the proposed Bhutan-to-Burma (B2B) Connected Landscape, a 1,400 km biodiversity corridor across northeast India.

     

  • Two billion people don’t have safe drinking water

    Why in the News?

    It’s shocking that 2 billion people around the world still don’t have access to safe drinking water, even though 95% of the global population uses what are called “improved water sources”. This reveals a hidden but serious public health problem.

    IBAT Alliance

    What defines ‘safe drinking water’?

    Safe drinking water refers to water that is free from harmful contaminants such as bacteria, viruses, and chemicals. It must be located on the premises, readily available when needed, and safe to consume without causing health issues.

    How does access vary across populations?

    • Majority Have Access, but Not Always at Home: While nearly 6 billion people have access to drinking water, around 2 billion still lack safe water at home.  Just 156 million people (around 1.4% of the global population) still collect water from unsafe sources like rivers or lakes.  
    • Disparities Exist Across Income and Geography: People in low-income or rural areas are more likely to lack access to safe, on-premises water. In most parts of Sub-Saharan Africa and South Asia, people still get their water from open sources such as rivers and lakes.

    How does a lack of safe water impact public health in poor countries?

    • Spread of Waterborne Diseases: Unsafe water is a major source of diarrhoeal diseases like cholera, dysentery, polio, and hepatitis A. Over 800,000 deaths annually are attributed to waterborne illnesses, especially in low-income nations with inadequate sanitation.
    • Child Mortality and Malnutrition: Contaminated water contributes to malnutrition, as diarrhoeal diseases hinder nutrient absorption in children. In India, nearly 21% of children under five suffer from wasting (NFHS-5), with poor water and sanitation as key contributors. 
    • Healthcare Burden and Economic Loss: Frequent illness from unsafe water overwhelms fragile public health systems and reduces workforce productivity. In India, poor access to safe water and sanitation leads to an annual GDP loss of over 4% due to health and productivity issues (Ministry of Jal Shakti, 2021). 

    SDG Goal 6 (Clean Water): Progress and challenges since its adoption 

    • Progress in Access to Improved Water Sources: As of recent estimates, 95% of the global population uses an improved water source like piped water, borewells, and springs, even in many low-income countries.
    • Challenge of Household-Level Accessibility: Despite improvements, safe water is often not available at home, requiring people—mostly women—to travel long distances. Around 1.5 billion people still lack on-premise access, which limits reliability and increases the risk of contamination during transport.
    • Polluted water at the point of use: Water may be clean at the source, but it becomes contaminated during collection, storage, or transport.  

    What are the alternative technologies which can solve this crisis?

    • Desalination Technology: Converts seawater into freshwater by removing salts and impurities using methods like reverse osmosis. Israel’s Sorek Desalination Plant provides 20% of the country’s water supply.
    • Solar Water Disinfection (SODIS): Uses UV rays from sunlight to kill bacteria and viruses in water stored in transparent bottles. It is widely used in rural Africa and India by households.
    • Atmospheric Water Generators (AWG): Extracts moisture from humid air and condenses it into clean drinking water. It was deployed in Rajasthan and UAE for areas with limited water but high humidity.

    What are the steps taken by the Government?

    • Jal Jeevan Mission (JJM): Aims to provide functional household tap connections (FHTCs) with safe and adequate drinking water to all rural households by 2024. Eg: As of 2024, over 13 crore rural households have been provided with tap water connections under JJM.
    • Swachh Bharat Mission and Water Quality Monitoring: Focuses on reducing open defecation and water contamination by improving sanitation infrastructure and promoting hygiene.  
    • Atal Mission for Rejuvenation and Urban Transformation (AMRUT): Ensures universal water supply coverage in urban areas, with a focus on poor and underserved households. Under AMRUT, cities like Surat and Nagpur have significantly improved their 24×7 piped water supply networks.

    Way forward

    • Strengthen Last-Mile Delivery through Infrastructure Expansion: Focus on household-level water connections, especially in rural and remote regions, by upgrading existing water supply networks and ensuring regular quality checks.
    • Promote Community-Based Water Management and Awareness: Encourage local governance (Panchayats, SHGs) and water user groups to manage water resources and promote safe water handling practices.

    Mains PYQ:

    [UPSC 2024] The world is facing an acute shortage of clean and safe freshwater. What are the alternative technologies which can solve this crisis? Briefly discuss any three such technologies, citing their key merits and demerits.

    Linkage: The artice talks about the emphasizes that for water to be considered “safe drinking water,” it must be “free from contamination, located at home, and available whenever needed. This question directly addresses the global issue of an “acute shortage of clean and safe freshwater”. This directly aligns with the core problem presented in the article , which states that “two billion people” still do not have safe drinking water in their homes.

  • Climate Threat Emerging from Rising Evaporative Demand and Thirstwaves

    Why in the News?

    Scientists have coined a new term, “thirstwave”, to describe spikes in evaporative demand, where a warmer atmosphere draws more water from plants, soil, and trees.

    What is Evaporative Demand?

    • Definition: Evaporative demand is the measure of how much water the atmosphere can potentially absorb from land, plants, and water surfaces if there is unlimited water available. It tells us how “thirsty” the atmosphere is.
    • Nature of Measurement: It is not about how much water is actually lost but how much could be lost if water was fully available. It depends on weather conditions, not the amount of water in the soil.
    • Standard Metric: The most widely used metric to quantify this is Standardized Short-Crop Reference Evapotranspiration (ETos)—which assumes a 12 cm grass surface with unlimited water availability.
    • Impact of Global Warming: As global warming increases atmospheric heat, evaporative demand also rises, making the air more “thirsty”.

    What is a Thirstwave?

    • Origin: “Thirstwave” is a newly coined term (2025) by Meetpal Kukal and Mike Hobbins to describe three or more consecutive days of extreme evaporative demand.
    • Definition: A thirstwave is a period of sudden and intense increase in evaporative demand, caused by hot, dry, and sunny weather. It means the atmosphere becomes extremely “thirsty” and starts pulling water rapidly from soil, plants, and water bodies, even if they already have limited moisture.
    • Distinction from Heatwaves: Unlike heatwaves, thirstwaves account for multifactorial stress, combining temperature, humidity, wind, and solar input.
    • Thirstwave in India: There is no dedicated data yet on thirstwaves in India, but researchers are beginning to investigate, especially in South Asia’s climate-vulnerable zones.
    [UPSC 2018] Which of the following leaf modifications occur(s) in the desert areas to inhabit water loss?

    1. Hard and waxy leaves

    2. Tiny leaves

    3. Thorns instead of leaves

    Select the correct answer using the code given below:

    Options: (a) 2 and 3 only (b) 2 only (c) 3 only (d) 1, 2 and 3 *

     

  • Rising Evaporative Demand and Thirstwaves

    Why in the News?

    Scientists have coined a new term, “thirstwave”, to describe spikes in evaporative demand, where a warmer atmosphere draws more water from plants, soil, and trees.

    What is Evaporative Demand?

    • Definition: Evaporative demand is the measure of how much water the atmosphere can potentially absorb from land, plants, and water surfaces if there is unlimited water available. It tells us how “thirsty” the atmosphere is.
    • Nature of Measurement: It is not about how much water is actually lost but how much could be lost if water was fully available. It depends on weather conditions, not the amount of water in the soil.
    • Standard Metric: The most widely used metric to quantify this is Standardized Short-Crop Reference Evapotranspiration (ETos)—which assumes a 12 cm grass surface with unlimited water availability.
    • Impact of Global Warming: As global warming increases atmospheric heat, evaporative demand also rises, making the air more “thirsty”.
    • Key Features:
      • Simplified Model: ETos simplifies evapotranspiration by assuming fixed vegetation properties and only variable weather conditions.
      • Indicators of Stress: An increase in ETos indicates higher temperatures, lower humidity, faster wind, and stronger solar radiation.
      • Effect on Soil and Crops: Rising evaporative demand leads to more rapid drying of soil and plants, even with ample irrigation.
      • Agricultural Relevance: This directly affects irrigation scheduling, crop productivity, and climate-resilient farming strategies.

    What is a Thirstwave?

    • Origin: “Thirstwave” is a newly coined term (2025) by Meetpal Kukal and Mike Hobbins to describe three or more consecutive days of extreme evaporative demand.
    • Definition: A thirstwave is a period of sudden and intense increase in evaporative demand, caused by hot, dry, and sunny weather. It means the atmosphere becomes extremely “thirsty” and starts pulling water rapidly from soil, plants, and water bodies, even if they already have limited moisture.
    • Distinction from Heatwaves: Unlike heatwaves, thirstwaves account for multifactorial stress, combining temperature, humidity, wind, and solar input.
    • Thirstwave in India: There is no dedicated data yet on thirstwaves in India, but researchers are beginning to investigate, especially in South Asia’s climate-vulnerable zones.
    [UPSC 2018] Which of the following leaf modifications occur(s) in the desert areas to inhabit water loss?

    1. Hard and waxy leaves

    2. Tiny leaves

    3. Thorns instead of leaves

    Select the correct answer using the code given below:

    Options: (a) 2 and 3 only (b) 2 only (c) 3 only (d) 1, 2 and 3 *

     

  • What is the Integrated Biodiversity Assessment Tool (IBAT) Alliance?

    Why in the News?

    The IBAT Alliance, a coalition of leading global conservation bodies, announced a record $2.5 million investment in biodiversity data for the year 2024, more than double the amount in 2023.

    About Integrated Biodiversity Assessment Tool (IBAT):

    • What is it: IBAT is a web-based biodiversity mapping and reporting platform launched in 2008 at the IUCN World Conservation Congress.
    • Objective: It was launched to enable the private sector, government, and civil society to integrate biodiversity into planning and risk management processes.
    • Utility: It helps screen biodiversity risks, assess conservation priorities, and align business practices with global frameworks like the UN SDGs and Kunming-Montreal Global Biodiversity Framework.
    • Members: The IBAT Alliance is a coalition of 4 major global conservation organizations:
      1. BirdLife International
      2. Conservation International (CI)
      3. International Union for Conservation of Nature (IUCN)
      4. UN Environment Programme World Conservation Monitoring Centre (UNEP-WCMC)
    • Headquarters: David Attenborough Building, Cambridge (UK), with access to global scientific and conservation networks.
    [UPSC 2016] With reference to an initiative called ‘The Economics of Ecosystems and Biodiversity (TEEB)’, which of the following statements is/are correct?

    1. It is an initiative hosted by UNEP, IMF and World Economic Forum.

    2. It is a global initiative that focuses on drawing attention to the economic benefits of biodiversity.

    3. It presents an approach that can help decision-makers recognize, demonstrate and capture the value of ecosystems and biodiversity.

    Select the correct answer using the code given below.

    (a) 1 and 2 only (b) 3 only (c) 2 and 3 only* (d) 1, 2 and 3

     

  • WMO’s State of the Climate in Asia 2024 Report

    Why in the News?

    The World Meteorological Organisation (WMO) has released its “State of the Climate in Asia, 2024” report.

    About the World Meteorological Organisation (WMO):

    • Overview: It is a specialised agency of the United Nations that deals with meteorology (weather and climate), operational hydrology, and related geophysical sciences.
    • Historical Origin: It was established in 1950, evolving from the International Meteorological Organisation (IMO), which was founded in 1873.
    • Headquarters Location: The headquarters of WMO is located in Geneva, Switzerland.
    • Global Coordination Role: WMO plays a key role in coordinating international efforts for climate data collection, forecasting, disaster preparedness, and climate change assessment.
    • Members: It has a membership of 193 members (187 member states + 6 Territories), including India.
    • Flagship Reports: WMO publishes annual climate reports such as the “State of the Climate” to highlight key trends and extreme weather impacts.

    Key Highlights of the State of the Climate in Asia – 2024 Report:

    • Record Warmth: 2024 was the warmest year on record in Asia, with heatwaves, extreme rainfalls, cyclones, and droughts devastating the region.
    • Global Temperature Spike: The global mean temperature reached its highest level since 1850, surpassing the 2023 record of 1.45°C.
    • Glacier Loss: 23 out of 24 monitored glaciers in the Himalayas and Tian Shan suffered mass loss, increasing the risk of glacial lake outburst floods (GLOFs).
    • Marine Heatwaves: Marine heatwaves of unprecedented extent and intensity affected Asian oceans, particularly around India, Japan, and China.
    • Major Cyclones: Cyclone Remal struck Bangladesh and India with 111 km/h winds and 2.5-metre-high storm surges; Asna and Fengal also caused major damage in Oman, Sri Lanka, and India.
    • Flash Floods and Landslides: Flash floods and landslides in Kerala, Nepal, and Sri Lanka resulted in hundreds of deaths and mass displacement.
    • Extreme Heatwaves: Heatwaves broke records across East and South Asia, including Japan, South Korea, China, Thailand, and India. Myanmar set a new national record at 48.2°C.
    • Severe Drought in China: Drought in China affected 4.8 million people, damaged over 335,000 hectares of crops, and caused losses of CNY 2.89 billion.
    [UPSC 2018] Momentum for Change: Climate Neutral Now” is an initiative launched by

    Options: (a) The Intergovernmental panel on Climate Change (b) The UNEP Secretariat (c) The UNFCCC Secretariat* (d) The World Meteorological Organization

     

  • All about the revised Green India Mission to increase forest cover, address climate change

    Why in the News?

    The revised plan for the Green India Mission (GIM), released by the Centre on June 17, is an important step forward in India’s fight against climate change.

    What are the achievements of the Green India Mission since its launch in 2014?

    • Large-scale Afforestation Activities: GIM facilitated tree plantation and afforestation across 11.22 million hectares between 2015–16 and 2020–21. Eg: Afforestation under state schemes in Andhra Pradesh and Telangana helped increase green cover.
    • Support to Vulnerable States: Funds were allocated based on ecological vulnerability and restoration potential. Eg: ₹624.71 crore released to 18 states between 2019–24, with ₹575.55 crore utilised.
    • Carbon Sequestration Contribution: Contributed to creating an additional carbon sink of 2.29 billion tonnes of CO₂ equivalent between 2005–2021. Eg: Forest restoration in Jharkhand and Chhattisgarh aided national climate goals.
    • Integration with Climate Goals: GIM aligned with India’s international commitment to restore 26 million hectares of degraded land by 2030. Eg: Activities under GIM complement India’s UNFCCC goals on land restoration and carbon capture.
    • Livelihood Enhancement through Forest-Based Interventions: Helped improve livelihoods of forest-dependent communities via sustainable forestry practices. Eg: Community plantation models in Odisha created jobs and promoted conservation.

    What are the key elements of the revised Green India Mission roadmap?

    • Landscape-level restoration: Focus on saturation-based, area-specific restoration in vulnerable landscapes like the Aravallis, Western Ghats, Himalayas, and mangroves.
    • Integration with flagship projects: Syncing with initiatives like the Aravalli Green Wall project (cost: Rs 16,053 crore, coverage: 6.45 mha across 29 districts and 4 states).
    • Aravalli protection: Targeting 8 lakh hectares for forest, water system and grassland rejuvenation to curb sandstorm intrusions and pollution in NCR and Punjab.
    • Western Ghats focus: Addressing illegal mining and deforestation through afforestation and abandoned mine rehabilitation.

    Why was the Green India Mission’s roadmap revised?

    • To Address On-Ground Climate Impacts: The revision was made to respond to changing climate conditions and the increasing urgency of land degradation and desertification. Eg: Inclusion of the Aravalli Green Wall Project to counter desert expansion from the Thar region.
    • To Incorporate Feedback from States and Scientific Bodies: The revised plan reflects inputs from implementing states and scientific institutions, ensuring region-specific solutions. Eg: Feedback led to the addition of eco-restoration of abandoned mining areas in the Western Ghats.
    • To Focus on Region-Specific Restoration Practices: The update prioritises landscape-specific and ecologically appropriate restoration in vulnerable ecosystems. Eg: Special emphasis on Himalayas, mangroves, and degraded zones for carbon sequestration and biodiversity conservation.

    What key regions will it now focus on?

    Who is implementing the Green Wall project?

    • Central Government Leadership: The Centre (Government of India) is spearheading the initiative, allocating funding and coordinating implementation across states. Eg: The project’s ₹16,053 crore budget and planning is directed by central agencies in collaboration with local authorities.
    • Collaboration with States and Scientific Institutions: Implementation involves three states (Haryana, Rajasthan, Gujarat), one UT (Delhi)  and guidance from the Wildlife Institute of India (WII), using ecological data to target 12 degradation gaps in the Aravalli range. Eg: WII studies identified dust-prone regions; restoration covers 8 lakh hectares across 29 districts in these states.

    How will GIM address land degradation and carbon sequestration?

    • Restoration of Degraded and Open Forests: GIM focuses on restoring impaired open forests, which is a cost-effective and high-impact method for carbon dioxide (CO₂) sequestration. Eg: As per the Forest Survey of India (FSI), restoring 15 million hectares can sequester 1.89 billion tonnes of CO₂.
    • Region-Specific Ecological Interventions: The revised roadmap includes landscape-specific afforestation and eco-restoration in vulnerable areas like the Aravallis, Western Ghats, Himalayas, and mangroves. Eg: Under the Aravalli Green Wall Project, 8 lakh hectares will be restored to combat desertification and reduce dust pollution.
    • Expansion of Natural Carbon Sinks: GIM aligns with India’s climate commitment to create an additional carbon sink of 2.5 to 3 billion tonnes of CO₂ by 2030. Eg: By integrating schemes and intensifying plantation efforts, GIM aims to expand forest and tree cover up to 24.7 million hectares, capturing 3.39 billion tonnes of CO₂.

    Way forward: 

    • Integrated Landscape-Based Planning: Adopt a holistic, ecosystem-specific approach by aligning GIM with other environmental programs (e.g., CAMPA, MGNREGS) for coordinated restoration and afforestation efforts.
    • Enhanced Monitoring and Community Participation: Use technology (GIS, remote sensing) for real-time progress tracking, while empowering local communities and forest-dependent groups for sustainable upkeep and livelihood generation.

    Mains PYQ:

    [UPSC 2020] Examine the status of forest resources of India and its resultant impact on climate change.

    Linkage: This question directly relates to the core objectives and context of the Green India Mission (GIM). The GIM, launched in 2014, is a crucial component of India’s efforts to combat climate change by increasing forest and tree cover and restoring degraded ecosystems. The revised roadmap for GIM emphasizes not only increasing and restoring forest and green cover but also tackling land degradation and desertification, which are significant environmental issues in India.

  • First Assembly of the International Big Cat Alliance (IBCA)

    Why in the News?

    The first Assembly of the International Big Cat Alliance (IBCA) was held on June 16, 2025, in New Delhi, with the Union Environment Minister presiding over the session.

    About the International Big Cat Alliance (IBCA)

    • Overview: It is a multi-country, multi-agency alliance of 95 countries, both range and non-range, dedicated to the conservation of big cats and their habitats.
    • Launch: Proposed by PM Modi in 2019, the alliance was officially launched in April 2023 to mark Project Tiger’s 50th anniversary.
    • Conservation Focus: IBCA seeks to protect and restore populations of 7 big cats: tiger, lion, leopard, snow leopard, cheetah, jaguar, and puma.
    • Core Functions: The alliance works through advocacy, knowledge exchange, promotion of eco-tourism, and resource mobilisation.
    • Conflict Resolution: It aims to reduce human-wildlife conflict and restore degraded habitats critical to big cat survival.
    • Global Participation: IBCA brings together 95 range countries from:
      • Asia: India, China, Nepal, Pakistan, Iran
      • Africa: Kenya, Congo, Ghana
      • Americas: Brazil, Ecuador, United States
      • Europe/Central Asia: Russia, Kazakhstan
    • Members: Bhutan, Eswatini, Cambodia, Guinea, India, Liberia, Nicaragua, Somalia and Suriname have deposited an instrument of ratification.
    • Institutional Structure: It is governed by a General Assembly, an elected Council, and a secretariat led by a Secretary-General.
    • Permanent Base: The ratification of the headquarters agreement has enabled IBCA to set up its permanent headquarters in India.

    India’s Role:

    • Species Richness: India is home to 5 of the 7 big cats—the tiger, lion, leopard, snow leopard, and cheetah—and holds 70% of the world’s tiger population.
    • Funding Commitment: The Indian government has committed ₹150 crore (2023–2028) and is attracting additional global contributions to support the alliance’s goals.
    • Conservation Leadership: India plays a leading global role in big cat protection, setting benchmarks in wildlife conservation and ecological stewardship.
    [UPSC 2024] Consider the following statements:

    1. Lions do not have a particular breeding season.

    2. Unlike most other big cats, cheetahs do not roar.

    3. Unlike male lions, male leopards do not proclaim their territory by scent marking.

    Which of the statements given above are correct?

    (a) 1 and 2 only * (b) 2 and 3 only (c) 1 and 3 only (d) 1, 2 and 2

     

  • Ocean Darkening: A New Ecological Crisis

    Why in the News?

    A new study from the University of Plymouth has revealed that over 21% of the global ocean has significantly darkened in the last two decades.

    What is Ocean Darkening?

    • Ocean darkening refers to the reduction in sunlight penetration into the ocean’s upper layers, known as the photic zone (up to 200 meters deep), where sunlight drives photosynthesis and supports marine biodiversity.
    • This process is measured using the diffuse attenuation coefficient (Kd 490), which tracks how quickly light diminishes as it passes through seawater.
    • The photic zone is essential for phytoplankton productivity, oxygen generation, marine food chains, and the regulation of global climate.

    Recent Report Citing Ocean Darkening:

    • A new study by researchers from the University of Plymouth, published in 2024, titled “Darkening of the Global Ocean”, revealed that 21% of the global ocean has significantly darkened from 2003 to 2022.
    • Key findings:
      • 9% of the ocean saw a drop of more than 50 meters in light penetration—equal to the area of Africa.
      • 2.6% experienced a loss exceeding 100 meters in photic depth.
    • Affected Region: The study found the Arctic, Antarctic, Gulf Stream, and North Sea among the worst affected regions.
    • Causes:
      • Algal blooms from nutrient runoff in coastal areas.
      • Warming seas, altered plankton dynamics, and changing ocean currents in open ocean zones.

    Implications of Ocean Darkening:

    • Ecosystem Disruption: Light-dependent species, such as Calanus copepods, are being pushed into shallower zones, increasing predation and competition.
    • Loss of Habitat: The shrinkage of the photic zone could be one of the largest marine habitat losses ever, affecting fish stocks and biodiversity.
    • Climate Feedback Loop: Reduced photosynthesis in oceans could weaken the ocean’s role in carbon sequestration and oxygen production, worsening climate change.
    • Threat to Global Fisheries: The contraction of productive zones affects fish populations, jeopardising fisheries and food security.
    • Scientific Concern: Researchers warn that this hidden crisis could fundamentally alter marine ecosystems if not urgently addressed.
    [UPSC 2025] 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 photosynthetic bacteria produce about 50% of the 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?

    Options: (a) I and II (b) II only * (c) I and III (d) None of the above statements is correct

     

  • [16th June 2025] The Hindu Op-ed: What are flue gas desulphurisation units?

    PYQ Relevance:

    [UPSC 2022] Discuss global warming and mention its effects on the global climate. Explain the control measures to bring down the level of greenhouse gases which cause global warming, in the light of the Kyoto Protocol, 1997.

    Linkage:  SO2 as “one of the major greenhouse gases that cause global warming”. Flue Gas Desulphurisation (FGD) units are designed specifically to remove SO2 emissions from the combustion of fossil fuels. Therefore, FGD units serve as a direct “control measure to bring down the level of greenhouse gases” as addressed by the question.

     

    Mentor’s Comment:  India’s top science advisory group has suggested ending the 2015 rule that made it compulsory for all coal-based power plants to install Flue Gas Desulphurisation (FGD) units. This has raised serious concerns because FGDs are key to reducing sulphur dioxide (SO₂) pollution, which causes 15% of India’s PM2.5 levels and leads to breathing problems, environmental damage, and climate change. Although installing FGDs is expensive (₹1.2 crore per MW), experts warn that dropping the plan could harm public health and clean air efforts. Worryingly, only 39 of 537 plants have installed FGDs, and deadlines keep getting pushed back.

     Today’s editorial focuses on the analysis of the installation of the Flue Gas Desulphurisation (FGD) units in a thermal power plant. This content is very relevant to GS Paper III (Environment, Science and Technology) Mains.

    _

    Let’s learn!

    Why in the News?

    A group of experts, led by Principal Scientific Advisor Ajay Sood, has recently suggested that India should cancel the 10-year-old rule that requires all coal-based thermal power plants to install Flue Gas Desulphurisation (FGD) units.

    Why India should cancel the 10-Year-Old Rule (2015 FGD Mandate)?

    • High Installation Cost Burden: Installing FGD units costs around ₹1.2 crore per MW, which can significantly raise power generation costs and electricity tariffs. Eg: For 97,000 MW of new capacity, the cost would be about ₹97,000 crore, making power less affordable.
    • Delayed and Poor Implementation: Despite the 2015 rule, compliance has been dismal—only 39 out of 537 plants had FGDs installed by 2025. Eg: Repeated deadline extensions (up to 2029) show lack of feasibility and institutional capacity.
    • Limited Local Air Quality Impact in Some Areas: In certain regions, the contribution of SO₂ emissions from TPPs to PM2.5 levels is relatively small. Eg: In Delhi, most air pollution comes from other sources like vehicles and construction, so FGDs at distant plants may offer minimal benefit.

    What is a Flue Gas Desulphurisation (FGD) unit?

    • FGD units are devices used in coal-fired thermal power plants (TPPs) to remove sulphur dioxide (SO₂) from flue gas. Flue gas is a byproduct of burning fossil fuels and contains pollutants like SO₂, CO₂, NOx, and particulate matter.
    • Three common FGD technologies:
      • Dry sorbent injection (adds powdered limestone to flue gas).
      • Wet limestone treatment (reacts SO₂ with limestone slurry to form gypsum).
      • Sea water scrubbing (used near coastal areas).

    How does it reduce SO₂ emissions from thermal power plants?

    • Chemical Neutralisation Reaction: FGD units use alkaline substances like limestone or lime to react with acidic SO₂ in flue gas, converting it into stable, non-toxic compounds. Eg: In wet limestone FGD, SO₂ reacts with limestone slurry to form gypsum (CaSO₄·2H₂O), a harmless industrial byproduct.
    • Efficient Scrubbing Techniques: Technologies like wet scrubbers or dry sorbent injection physically remove SO₂ from exhaust gases before release into the atmosphere. Eg: Dry sorbent injection sprays powdered lime into the flue gas stream, which binds with SO₂ and is later captured by filters.
    • Controlled Emission Discharge: FGD ensures that the treated flue gas released into the environment has significantly lower SO₂ levels, complying with environmental norms. Eg: Power plants near coasts use sea water FGD, where sea water absorbs SO₂ and is then treated before being discharged safely.

    Why are SO₂ emissions harmful?

    • Respiratory and Health Issues: Sulphur dioxide (SO₂) irritates the respiratory system, causing problems like asthma, bronchitis, and lung damage, especially in children and the elderly. Eg: Studies in urban industrial areas show a direct link between SO₂ exposure and increased hospital admissions for respiratory illnesses.
    • Formation of Secondary Particulate Matter (PM2.5): SO₂ reacts in the atmosphere to form fine particulate matter (PM2.5), which can penetrate deep into lungs and enter the bloodstream, posing serious health risks. Eg: According to studies, 80% of PM2.5 from coal combustion is due to secondary particles formed from SO₂.
    • Contribution to Acid Rain: SO₂ combines with water vapor in the atmosphere to form sulphuric acid, leading to acid rain that damages soil, crops, forests, and aquatic ecosystems. Eg: Regions near coal-fired plants have reported acidic lakes and damaged crops due to acid rain deposition.
    • Environmental Degradation: High SO₂ levels can corrode buildings, especially monuments made of limestone or marble, and degrade overall air and water quality. Eg: The Taj Mahal has shown signs of yellowing, partly attributed to SO₂-related pollution.
    • Climate and Visibility Impact: Though SO₂ itself is not a greenhouse gas, it leads to formation of aerosols, affecting cloud formation, reducing visibility, and causing climate imbalance. Eg: In industrial belts, hazy skies and temperature variations are linked to SO₂-derived aerosols.

    What is the status of FGD installation in India (2025)?

    • Low Overall Commissioning: Only about 39 out of 537 thermal power plant units (≈ 19,430 MW capacity) have commissioned FGD systems, representing ~11% of the total required capacity. Eg: Just 13 out of 35 units within 300 km of Delhi have installed FGDs, showing slow progress in high-pollution zones.
    • Stalled Projects and Delays: Contracts have been awarded for about 238 units (~105,200 MW), and 139 units (~42,847 MW) are still in the tendering stage, but many projects remain stalled. Eg: Some plants, especially near Delhi, may take up to 36 months to complete FGD installation due to regulatory and logistical hurdles.
    • Repeated Deadline Extensions: Compliance deadlines have been extended multiple times: from 2017 → 2024 → 2026–2029, depending on the location and plant category. Eg: The Ministry of Environment has pushed back deadlines for thermal plants in Delhi NCR without strict justification, raising concerns about enforcement.

    Way forward: 

    • Prioritised FGD Installation: Expedite FGD implementation in high-emission and densely populated zones to balance cost and health impact.
    • Policy and Financial Support: Provide targeted subsidies or incentives to TPPs and integrate FGD costs into long-term tariff planning for smoother adoption.