UPSC Prelims 2018
Environment & Ecology Previous Year Questions (PYQs)

Detailed Explanation:

Answer: Option 4 — Neither 1 nor 2

Both statements about solar power production in India are incorrect. India is not among the top three global manufacturers of silicon wafers for photovoltaic units, and SECI does not determine solar power tariffs but facilitates project implementation.

❌ Statement 1 – Incorrect: India does not rank among the top three manufacturers of silicon wafers for photovoltaic units; China, Taiwan, and South Korea dominate this sector with China alone accounting for over 90% of global production.

❌ Statement 2 – Incorrect: The Solar Energy Corporation of India (SECI) does not determine solar power tariffs; tariffs are determined through a competitive bidding process conducted by various implementing agencies, with SECI acting as a facilitator and intermediary.

📝 Short Notes: Solar Power in India

• Solar Energy Corporation of India (SECI): A government-owned enterprise under the Ministry of New and Renewable Energy (MNRE), established in 2011 to facilitate solar energy deployment through competitive bidding, tendering, and project implementation.
• Tariff Determination: Solar power tariffs in India are market-driven and determined through reverse auction mechanisms where developers bid competitively; the lowest bidder wins the contract, ensuring cost-effective power procurement.
• Silicon Wafer Manufacturing: India's domestic solar manufacturing capacity is limited, with heavy reliance on imports (especially from China) for solar cells, modules, and silicon wafers; the government is promoting domestic manufacturing through Production Linked Incentive (PLI) schemes.
• Global Leaders: China dominates global solar manufacturing with over 90% market share in silicon wafers, followed by Taiwan and South Korea; India is focusing on building manufacturing capacity through policies like Atmanirbhar Bharat.
• India's Solar Capacity: India ranks among the top 5 countries globally in installed solar capacity and aims to achieve 500 GW of renewable energy capacity by 2030 as part of its climate commitments.

Detailed Explanation:

Answer: Option 1 — Arunachal Pradesh

Pakhui Wildlife Sanctuary is located in the East Kameng district of Arunachal Pradesh. It is part of the Kameng Elephant Reserve and is contiguous with Pakke Tiger Reserve, known for its rich biodiversity including hornbills, elephants, and tigers. The sanctuary is traversed by the Bhareli (Pakke) and Bamadi rivers, supporting diverse flora and fauna.

📝 Short Notes: Major Wildlife Sanctuaries in Northeast India

Detailed Explanation:

Answer: Option 4 — 2, 4 and 5

Conservation Agriculture is based on three core principles: minimum soil disturbance (minimum/no tillage), permanent soil cover (using crop residues or mulches), and crop diversification (through rotations and intercropping). Options 2, 4, and 5 directly align with these principles, while options 1 and 3 are not recognized components of Conservation Agriculture.

✅ Statement 2 – Correct: Minimum tillage is a fundamental principle of Conservation Agriculture that reduces soil disturbance and erosion.
❌ Statement 1 – Incorrect: While crop diversification is encouraged, avoiding monoculture is not explicitly defined as a Conservation Agriculture practice.
❌ Statement 3 – Incorrect: Conservation Agriculture does not exclude plantation crops; these can be cultivated using conservation practices.
✅ Statement 4 – Correct: Maintaining permanent soil cover using crop residues is a core principle of Conservation Agriculture.
✅ Statement 5 – Correct: Crop rotations and sequencing are essential for crop diversification under Conservation Agriculture.

📝 Short Notes: Conservation Agriculture

• Definition: A sustainable farming system based on three interlinked principles that enhance agricultural productivity while protecting the environment.
• Three Core Principles:
  • Minimum Soil Disturbance: No-till or minimum tillage farming reduces soil erosion and improves soil structure.
  • Permanent Soil Cover: Use of crop residues, mulches, or cover crops to protect soil from erosion and maintain moisture.
  • Crop Diversification: Crop rotations, intercropping, and crop sequencing to improve soil fertility and break pest cycles.
• Benefits: Reduces soil erosion, improves water retention, enhances soil organic matter, reduces input costs, and increases resilience to climate variability.
• FAO Support: The Food and Agriculture Organization (FAO) actively promotes Conservation Agriculture globally as a climate-smart practice.
• Application in India: Particularly relevant in water-stressed regions and areas with declining soil health; promoted through various government schemes.

Detailed Explanation:

Answer: Option 4 — Mankind's over-exploitation/misuse of natural resources, fragmentation/loss of natural habitats, destruction of ecosystems, pollution and global climate change.

The term "sixth mass extinction" refers to the ongoing biodiversity crisis driven primarily by anthropogenic (human-caused) factors. Unlike previous mass extinctions caused by natural phenomena, the current extinction event is characterized by unprecedented rates of species loss due to human activities including habitat destruction, overexploitation of species, pollution, introduction of invasive species, and climate change. Scientists estimate that species are currently going extinct at rates 100 to 1,000 times higher than the natural background rate, making this a human-driven ecological catastrophe comparable to the five previous mass extinctions in Earth's 4.5-billion-year history.

📝 Short Notes: Mass Extinctions

• Current extinction rate: 100-1,000 times higher than natural background rate
• Primary drivers: Habitat loss (deforestation, urbanization), overexploitation (hunting, fishing), pollution, invasive species, climate change
• Most affected groups: Amphibians, marine mammals, large predators, island species
• IUCN Red List: Over 40,000 species currently threatened with extinction
• Holocene extinction: Another name for the sixth extinction, referring to the current geological epoch

Detailed Explanation:

Answer: Option 3 — The UNFCCC Secretariat

The "Momentum for Change: Climate Neutral Now" initiative was launched by the United Nations Framework Convention on Climate Change (UNFCCC) Secretariat in 2015 to encourage individuals, businesses, and governments to take voluntary action towards climate neutrality. In 2016, Climate Neutral Now became a new pillar under the broader "Momentum for Change" initiative, which highlights and promotes successful climate action worldwide.

📝 Short Notes: Climate Neutral Now Initiative

• Launch: Launched by UNFCCC Secretariat in 2015 to promote voluntary climate action towards climate neutrality
• Three-Step Process: (1) Measure climate footprint (greenhouse gas emissions), (2) Reduce emissions through sustainable practices and efficiency improvements, (3) Offset unavoidable emissions using UN-certified emission reductions (CERs)
• Momentum for Change: Climate Neutral Now was integrated as a pillar under the broader "Momentum for Change" initiative in 2016
• Target Audience: Individuals, companies, and governments worldwide
• Alignment: Supports Paris Agreement goals by fostering accountability and proactive engagement in climate action
• Recognition: Part of UNFCCC's efforts to showcase and scale up innovative climate solutions globally

Detailed Explanation:

Answer: Option 1 — Increased plant growth due to increased concentration of carbon dioxide in the atmosphere

Carbon fertilization refers to the phenomenon where elevated atmospheric CO₂ concentrations enhance the rate of photosynthesis in plants, leading to increased plant growth and biomass production. Since CO₂ is a key substrate for photosynthesis, higher concentrations allow plants to synthesize more sugars (glucose), thereby accelerating growth rates. This effect is distinct from global warming (temperature increase), ocean acidification, or adaptive responses to climate change.

📝 Short Notes: Carbon Fertilization and Plant Physiology

• Carbon Fertilization: The enhancement of photosynthetic rates and plant growth due to elevated atmospheric CO₂ levels.
• Photosynthesis Basics: Plants absorb CO₂, water, and sunlight to produce glucose (C₆H₁₂O₆) and release oxygen (O₂) as a byproduct.
• Current CO₂ Levels: Atmospheric CO₂ concentration has reached approximately 420 ppm (as of recent measurements), the highest in millions of years, primarily due to fossil fuel combustion and deforestation.
• Growth Response: Many C3 plants (wheat, rice, soybeans) show significant growth enhancement with increased CO₂, though C4 plants (maize, sugarcane) show less response.
• Limitations: Carbon fertilization benefits are limited by other factors like nutrient availability (nitrogen, phosphorus), water stress, and temperature extremes.
• Ecosystem Impacts: While increased plant growth may sequester more carbon, this effect is offset by increased respiration, decomposition, and other climate change impacts.

Detailed Explanation:

Answer: Option 2 — The United Nations Conference on Sustainable Development 2012, Rio de Janeiro

The Partnership for Action on Green Economy (PAGE) was established in response to the United Nations Conference on Sustainable Development (UNCSD) 2012, also known as Rio+20, held in Rio de Janeiro, Brazil. This conference reaffirmed global commitment to sustainable development and emphasized the transition to green economies that promote environmental sustainability, social inclusion, and economic growth. PAGE was launched as a UN collaborative initiative involving UNEP, ILO, UNDP, UNIDO, and UNITAR to support countries in developing policies and strategies for sustainable and inclusive economic growth.

📝 Short Notes: Major UN Conferences on Sustainable Development

• PAGE Partner Agencies: UNEP (lead), ILO, UNDP, UNIDO, UNITAR
• PAGE Objective: Support countries in reframing economic policies and practices around sustainability
• Focus Areas: Green industrial policy, sustainable consumption and production, green fiscal reform, ecosystem services, and inclusive growth

Detailed Explanation:

Answer: Option 1 — 1 and 2 only

This question tests knowledge of the Forest Rights Act, 2006, particularly regarding Critical Wildlife Habitats and Habitat Rights for Particularly Vulnerable Tribal Groups (PVTGs). Statement 3 is incorrect because State governments, not the Union Ministry, have the authority to declare Habitat Rights.

✅ Statement 1 – Correct: The Forest Rights Act, 2006 explicitly defines "Critical Wildlife Habitat" as areas within National Parks and Wildlife Sanctuaries that require inviolate conservation for wildlife protection, and can only be declared based on scientific evidence after due process of resettlement.

✅ Statement 2 – Correct: In 2015, the Baiga tribal community in Madhya Pradesh became the first in India to be granted Habitat Rights under the FRA, 2006, allowing them to continue living in the Kanha Tiger Reserve buffer zone with access to forest resources.

❌ Statement 3 – Incorrect: Under the Forest Rights Act, 2006, it is the State governments (not the Union Ministry) that have the authority to declare and vest Habitat Rights for Primitive Tribal Groups after obtaining consent from the concerned communities and establishing resettlement measures.

📝 Short Notes: Forest Rights Act, 2006 — Key Provisions

• Official Title: The Scheduled Tribes and Other Traditional Forest Dwellers (Recognition of Forest Rights) Act, 2006
• Critical Wildlife Habitat (CWH): Defined under Section 2(b) as areas within National Parks and Wildlife Sanctuaries that require inviolate conservation for wildlife protection; can be notified only after scientific evidence and completion of resettlement process
• Habitat Rights: Under Section 3(1)(e), Primitive Tribal Groups (now called Particularly Vulnerable Tribal Groups - PVTGs) and pre-agricultural communities are entitled to habitat rights for habitation and livelihood
• Authority: State governments have the power to declare Habitat Rights after obtaining consent from Gram Sabhas and affected communities
• First Grant: Baiga tribe in Madhya Pradesh (2015) was the first PVTG to receive Habitat Rights in Kanha Tiger Reserve buffer zone
• PVTGs in India: 75 tribal groups across 18 states are classified as Particularly Vulnerable Tribal Groups based on criteria like pre-agricultural level of technology, low literacy, and declining population

Detailed Explanation:

Answer: Option 2 — 2 only

The Global Alliance for Climate-Smart Agriculture (GACSA) is a voluntary multi-stakeholder platform that does not impose binding obligations on its members. Only statement 2 is correct, while statements 1 and 3 contain factual errors regarding GACSA's origins and India's role.

❌ Statement 1 – Incorrect: GACSA was launched in 2014 at the UN Climate Summit in New York, not at the Paris Climate Summit in 2015.
✅ Statement 2 – Correct: GACSA is a voluntary partnership platform, and membership does not create any legally binding obligations for its members.
❌ Statement 3 – Incorrect: GACSA was launched by the Netherlands, FAO, and other countries at the UN Climate Summit in New York; India was not instrumental in its creation.

📝 Short Notes: Global Alliance for Climate-Smart Agriculture (GACSA)

• Launch: September 2014 at UN Climate Summit, New York
• Initiators: Netherlands, FAO (Food and Agriculture Organization), and other partner countries
• Nature: Voluntary, multi-stakeholder platform with no binding legal obligations
• Objective: Promote Climate-Smart Agriculture (CSA) to enhance food security, adapt to climate change, and reduce greenhouse gas emissions
• Membership: Open to governments, international organizations, civil society, private sector, and research institutions
• Three Pillars of CSA: (1) Sustainably increase agricultural productivity and incomes, (2) Adapt and build resilience to climate change, (3) Reduce greenhouse gas emissions where possible
• India's Position: India has been cautious about GACSA and has not been a founding or leading member; concerns relate to potential impacts on smallholder farmers

Detailed Explanation:

Answer: Option 2 — It tends to reduce the biodiversity in the area in which it grows.

Prosopis juliflora, commonly known as mesquite, is frequently mentioned in news due to its invasive nature and negative impact on native ecosystems. Originally introduced for afforestation and erosion control, it rapidly spreads and forms dense thickets that outcompete native vegetation, thereby reducing biodiversity. Its aggressive growth pattern disrupts ecological balance and has led to efforts in states like Tamil Nadu to remove it and restore native habitats.

📝 Short Notes: Prosopis juliflora (Mesquite)

• Origin: Native to Central and South America; introduced to Africa, Asia, and Australia for afforestation, erosion control, and fuelwood.
• Common names: Mesquite, Thorn Mimosa, Vilayati Babul, Seemai Karuvelam (Tamil Nadu).
• Invasive characteristics: Rapid growth rate, drought tolerance, prolific seed production, and deep root system allowing survival in harsh conditions.
• Ecological impact: Forms dense thickets that prevent growth of native plants; reduces biodiversity; depletes soil moisture and nutrients; alters habitat structure.
• Current status in India: Declared invasive species in several states; particularly problematic in Tamil Nadu, Gujarat, and Rajasthan; removal and restoration programs underway.
• Uses: Despite invasive nature, used for fuelwood, charcoal, fodder (pods), and timber; pods contain high protein content.

Detailed Explanation:

Answer: Option 2 — 2 and 3 only

Heavy sand mining in riverbeds disrupts the natural filtration system and hydrological balance, leading to groundwater pollution and lowering of water tables. It does not decrease salinity; rather, in coastal areas, it can increase salinity through saltwater intrusion.

❌ Statement 1 – Incorrect: Sand mining does not decrease salinity; in coastal/estuarine regions, it actually increases salinity by allowing saltwater intrusion from the sea into the river system.

✅ Statement 2 – Correct: River sand acts as a natural filter; its removal reduces filtration capacity, allowing pollutants, heavy metals, and contaminants to seep into groundwater aquifers.

✅ Statement 3 – Correct: Heavy sand mining causes riverbed incision (deepening), which lowers the base level, causing surrounding groundwater to drain into the deepened channel and significantly lowering the water table in adjacent areas.

📝 Short Notes: Environmental Impacts of Sand Mining

• Riverbed Incision: Excessive sand extraction deepens river channels, destabilizing riverbeds and banks, leading to erosion and infrastructure damage (bridges, pipelines).
• Groundwater Depletion: Lowered riverbeds act as drains, pulling down the surrounding water table and affecting wells and agriculture in riparian zones.
• Loss of Natural Filtration: Sand and gravel layers naturally filter water; their removal compromises water quality and increases groundwater contamination risk.
• Saltwater Intrusion: In coastal areas, sand mining creates depression zones that facilitate inland movement of saline water, contaminating freshwater resources.
• Biodiversity Loss: Sand mining destroys aquatic habitats, spawning grounds for fish, and nesting sites for river fauna like turtles and crocodiles.
• Regulatory Framework: Environment (Protection) Act, 1986, and Ministry of Environment guidelines regulate sand mining; many states have banned riverbed sand mining.

Detailed Explanation:

Answer: Option 2 — 2 only

The question tests the distinction between NGT (a judicial body) and CPCB (a regulatory body). Only statement 2 correctly describes their respective roles, while statement 1 incorrectly claims CPCB was created by executive order.

❌ Statement 1 – Incorrect: Both NGT and CPCB are statutory bodies established by Acts of Parliament. NGT was established under the National Green Tribunal Act, 2010, while CPCB was constituted under the Water (Prevention and Control of Pollution) Act, 1974. Neither was created by executive order.

✅ Statement 2 – Correct: NGT is a specialized environmental court that provides fast-track justice for environmental disputes and reduces litigation burden on higher courts, whereas CPCB is a regulatory body responsible for monitoring and controlling pollution, including maintaining cleanliness of water bodies and improving air quality.

📝 Short Notes: NGT vs CPCB

Detailed Explanation:

Answer: Option 4 — 1 only

The Aral Sea has shrunk immensely due to extensive water diversion for irrigation from its feeder rivers (Amu Darya and Syr Darya) since the 1960s, losing over 75% of its area. The Black Sea, while facing pollution and ecological challenges, has not dried up or shrunk significantly. Lake Baikal experiences natural water level fluctuations but has not undergone severe drying like the Aral Sea.

✅ Statement 1 – Correct: The Aral Sea has shrunk by over 75% since the 1960s due to Soviet-era irrigation projects diverting its feeder rivers.
❌ Statement 2 – Incorrect: The Black Sea faces pollution and oxygen depletion issues but has not experienced significant shrinkage or drying.
❌ Statement 3 – Incorrect: Lake Baikal, the world's deepest freshwater lake, has not dried up or shrunk immensely despite some natural water level variations.

📝 Short Notes: Major Water Bodies Under Environmental Stress

• Aral Sea (Central Asia): Once the world's fourth-largest lake, it has lost ~90% of its volume since 1960 due to Soviet irrigation schemes. This has caused desertification, increased salinity, loss of fisheries, and creation of the Aralkum Desert with toxic dust storms.
• Dead Sea (Middle East): Shrinking at about 1 meter per year due to water diversion from the Jordan River and mineral extraction industries.
• Lake Chad (Africa): Has shrunk by ~90% since the 1960s due to climate change, drought, and irrigation demands from surrounding countries.
• Lake Urmia (Iran): Has lost ~80% of its surface area due to dam construction, agricultural water use, and prolonged drought.
• Lake Baikal (Russia): The world's deepest and oldest freshwater lake, containing ~20% of Earth's unfrozen freshwater. Faces pollution threats but remains stable in size.
• Black Sea: Faces eutrophication, anoxic zones, and pollution but maintains its overall size and water volume.

Detailed Explanation:

Answer: Option 4 — 1, 2 and 3

Desert plants have evolved multiple leaf modifications to minimize water loss through transpiration in arid environments. All three modifications mentioned—hard and waxy leaves, tiny leaves, and thorns instead of leaves—serve this purpose effectively.

✅ Statement 1 – Correct: Hard and waxy leaves have a thick cuticle layer and reduced stomata, which significantly limit water evaporation from the leaf surface.
✅ Statement 2 – Correct: Tiny leaves reduce the total surface area exposed to the atmosphere, thereby decreasing the potential for water loss through transpiration.
✅ Statement 3 – Correct: Thorns replacing leaves (as seen in cacti and other xerophytes) eliminate the primary transpiring surface, drastically reducing water loss while providing protection from herbivores.

📝 Short Notes: Xerophytic Adaptations in Desert Plants

• Leaf Modifications: Desert plants (xerophytes) exhibit structural adaptations to conserve water in water-scarce environments.
• Thick Cuticle: A waxy, waterproof coating reduces cuticular transpiration.
• Reduced Leaf Surface: Small or needle-like leaves (e.g., Acacia) minimize the area for water loss.
• Leaf Transformation to Spines: In cacti, leaves are modified into thorns, and photosynthesis occurs in green stems.
• Sunken Stomata: Stomata located in pits or grooves reduce air movement and water vapor loss.
• CAM Photosynthesis: Crassulacean Acid Metabolism allows stomata to open at night, reducing daytime water loss.
• Deep Root Systems: Extensive roots access groundwater, complementing above-ground water conservation strategies.