Environment and Ecology Mixed Practice — MCQs with Answers (Set 6)

Mineral depletion in India isn’t really about running out underground — it’s about processing and refining capacity, most of which sits in China, not India.

Correct because statements 2 and 3 are true, so only two are correct. PRANA, the portal for regulating non-attainment city action plans, tracks progress online. GRAP escalates emergency measures across four stages as the Air Quality Index worsens. NCAP itself is a strategy, not a law; enforcement relies on the Air Act and the Environment Protection Act.

Correct because a non-attainment city is one that repeatedly misses the National Ambient Air Quality Standards. NCAP now covers about 130 such and million-plus cities. Each must run a city-specific action plan.

Correct because the initial NCAP target was a 20–30% reduction in PM2.5 and PM10 concentrations by 2024, using 2017 as the base year. In September 2022 the government revised this to up to 40% for PM10 by 2025–26. The new base year is 2019–20.

Correct because NCAP is implemented by the Ministry of Environment, Forest and Climate Change. The ministry approves city action plans and reviews their progress. Other ministries join in for sectoral actions like transport and industry.

Correct because the Ministry of Environment, Forest and Climate Change launched NCAP in January 2019. It is India’s first national programme with city-level air quality targets. The 2022 revision raised its reduction goal, but the launch year remains 2019.

Correct because statement 2 is true and the others are false. Molisch’s definition included beneficial effects, so allelopathy is not always harmful. Allelopathic effects vary with concentration, soil type and microbial breakdown.

Correct because allelochemicals can leave plants through root exudates, volatile emissions, leaf leachates and decaying residues. Soil microbes and water can then carry them to neighbouring plants. Concentration and soil conditions decide how strong the effect is.

Correct because allelopathic rice varieties release compounds that inhibit weeds such as barnyard grass. This natural suppression cuts herbicide use in paddy fields. It fits integrated weed management in India’s irrigated rice systems.

Correct because black walnut roots and leaves release juglone, a classic allelochemical. Juglone inhibits tomatoes, potatoes and many other sensitive plants. It is one of the best-documented examples of allelopathy.

Correct because Hans Molisch, an Austrian botanist, coined the term allelopathy in 1937. His definition covered both harmful and beneficial chemical effects between plants. Modern usage stresses the suppressive effects on other plants.

Correct because statements 1 and 2 are right, so only two hold. Double-hull designs protect the cargo from breaches, and dispersants speed microbial breakdown. Statement 3 is wrong because tar balls persist for months to years, not weeks.

Correct because MARPOL, the International Convention for the Prevention of Pollution from Ships, regulates ship-borne pollution. It restricts oily discharge and requires waste-reception facilities at ports. India is a party to MARPOL and enforces it through national law.

Correct because oil mats feathers and breaks their natural waterproofing. The bird loses buoyancy and insulation, so it chills quickly or drowns. Birds also swallow oil while preening, which poisons them.

Correct because oil pollution means petroleum hydrocarbons entering the sea or coastal waters. Crude oil, refined fuels and oily ship waste are all forms of it. Tanker accidents, ship discharges and offshore drilling are the main sources.

Correct because all four statements hold. The 2021 Act created the National Dam Safety Authority. Overtopping and foundation issues top failure records. Typhoon Nina’s rain destroyed Banqiao in 1975. Piping is seepage-driven soil erosion inside a dam.

Correct because heavy rain produced a flood roughly three times the dam’s design capacity. The earthen embankments were overtopped and washed away. A wall of water then struck Morbi town downstream.

Correct because overtopping happens when floods fill the reservoir beyond the crest. The water then erodes the dam body. Extreme rain caused this at Machchhu II in 1979.

Correct because a dam failure is an uncontrolled release of the stored water. It usually follows a breach, a collapse or a structural rupture. The sudden flood devastates the downstream valley.

Correct because IPCC AR6 gives likely ranges for future sea-level rise. Under the highest emissions scenario, the likely rise by 2100 is 0.63 to 1.01 metres. The UPSC question’s ‘about one metre’ matches this upper scenario. Even lower scenarios bring serious coastal impact.

Correct because regional sea-level rise can exceed the global mean. Sinking deltas and land subsidence add local rise. Faster warming and shifting currents lift the Indian Ocean more. Together these factors explain the regional difference.

Correct because the Maldives is among the world’s flattest countries. Its average elevation is about 1.5 metres above the sea. Even a modest rise brings flooding, erosion and salt intrusion. The nation is therefore a frontline case for climate adaptation.

Correct because global sea-level rise has two main drivers. Warming oceans expand, which is thermal expansion. Melting glaciers and ice sheets add land ice to the sea. Together these set the pace of the rise worldwide.

The National Mission for Sustaining the Himalayan Ecosystem, or NMSHE, is one of the eight missions under India’s National Action Plan on Climate Change. It supports research, monitoring and adaptation across the Himalayan states. It works alongside eco-sensitive zones and community conservation on the ground.

A strict environmental impact assessment screens projects before approval, while eco-sensitive zone notification restricts damaging activity near protected areas. Used together they shield fragile mountain landscapes from unplanned development. Honest enforcement is what makes both tools work.