Pollution - Competency-Based Question Bank (with Answers)

Section A: Case-Based Questions

Case Study 1: Lake covered with algae, fish dying, village runoff.

Identify the phenomenon.
- Answer: Eutrophication (followed by Algal Bloom).
Nutrients responsible.
- Answer: Nitrates and Phosphates (from detergents and fertilizers).
Designing: Restoration methods.
- Answer: Diverting sewage away from the lake, and "Bioremediation" (using plants/microbes to absorb excess nutrients).
Analysis: Why are fish dying?
- Answer: Algae die and are decomposed by bacteria, which use up all the dissolved Oxygen in the water, causing fish to suffocate.
Define "BOD".
- Answer: Biological Oxygen Demand - the amount of dissolved oxygen needed by aerobic biological organisms to break down organic material in a water sample.

Case Study 2: City smog in winter, eye irritation. 6. Identify the pollution.

Answer: Smog (Smoke + Fog).

What is "Photochemical Smog"?
- Answer: Smog produced when sunlight reacts with nitrogen oxides and volatile organic compounds (from car exhausts).
Creating: Health advisory.
- Answer: "Wear N95 masks, avoid outdoor exercise in the morning, use air purifiers, and keep hydrated."
Critical Thinking: Stubble burning contribution.
- Answer: Releases massive amounts of smoke and particulate matter (PM) which get trapped in the cold, still air of winter (Temperature Inversion).
PM 2.5 and PM 10 role.
- Answer: These fine particles can penetrate deep into the lungs and even enter the bloodstream, causing asthma, bronchitis, and heart disease.

Section B: Assertion-Reasoning Questions

Directions: (a) Both A/R true, R explains A; (b) Both true, R doesn't explain A; (c) A true, R false; (d) A false, R true.

Assertion (A): Taj Mahal is turning yellow. Reason (R): Acid rain reacts with marble.
- Answer: (a) Both A and R are true and R is the correct explanation.
Assertion (A): Ozone in stratosphere is "Good Ozone". Reason (R): Shields from UV radiation.
- Answer: (a) Both A and R are true and R is the correct explanation.
Assertion (A): Plastic bags should be banned. Reason (R): They are non-biodegradable.
- Answer: (a) Both A and R are true and R is the correct explanation.
Assertion (A): CO2 is a Green House Gas. Reason (R): It traps infrared radiation.
- Answer: (a) Both A and R are true and R is the correct explanation.
Assertion (A): Noise pollution can cause hypertension. Reason (R): Loud noise increases adrenaline.
- Answer: (a) Both A and R are true and R is the correct explanation.

Section C: Creating and Designing (Application & Analysis)

Designing: Rainwater Harvesting.
- Answer: [Roof -> Pipes -> Filter -> Storage Tank -> Groundwater Recharge].
Creating: Slogan.
- Answer: "Clean India, Green India."
Analysis: Biodegradable vs Non-biodegradable.
- Answer: Biodegradable: Can be broken down by microbes (Paper, Food). Non-biodegradable: Cannot be broken down (Plastic, Glass, DDT).
Designing: Pollutants table.
- Answer: [CO: Car exhaust (suffocation). SO2: Factories (acid rain). DDT: Pesticide (Biomagnification). Mercury: Industrial waste (Minamata disease)].
Visualisation: Greenhouse Effect.
- Answer: [Description: Solar rays enter, but heat rays cannot escape through the layer of GHGs].
Application: Why ban CFCs?
- Answer: They release chlorine atoms in the stratosphere which break down Ozone ( $O_3$ ) molecules into Oxygen ( $O_2$ ), thinning the ozone layer.
Creating: Waste-to-Wealth.
- Answer: Making paper mache bowls or recycling into cardboard.
Analysis: Biomagnification of DDT.
- Answer: DDT concentration increases at each trophic level because it is not metabolized; it leads to thin eggshells in birds of prey.
Designing: Reduce Noise Pollution.
- Answer: Using silencers in machines, "No Honking" zones near hospitals, and planting trees (Green Muffler).
Creating: Speech on Single-Use Plastic.
- Answer: [Focus on ocean pollution, death of cattle/turtles, and microplastics in food].

Section D: Competency & Critical Thinking

Acid Rain.
- Answer: Rain containing nitric and sulfuric acids. pH below 5.6.
Scenario: Nuclear radiation risks.
- Answer: DNA damage leading to genetic mutations, leukemia, and other cancers.
Critical Thinking: Is Greenhouse Effect entirely bad?
- Answer: No, without it, the Earth's average temperature would be -18°C, too cold for most life. The problem is the enhanced effect.
Application: Scrubber/Precipitator.
- Answer: Used in chimney stacks to remove gases (Scrubber) or dust particles (Precipitator) from industrial smoke.
Pollutant vs Contaminant.
- Answer: Pollutant: Harmful substance that reduces quality of environment. Contaminant: Substance in the wrong place but not necessarily harmful yet.
Diagram Based: GHG pie chart.
- Answer: CO2 accounts for approx 60% of the enhanced greenhouse effect.
Oil Spills impact.
- Answer: Coats feathers of birds (hypothermia) and prevents gas exchange for marine life.
Analysis: Unleaded petrol.
- Answer: Lead is a neurotoxin; removing it prevents lead poisoning and allows the use of catalytic converters in cars.
Competency: BS-VI norms.
- Answer: Stringent standards for vehicle tailpipe emissions (CO, HC, NOx, and PM).
Case: Minamata disease.
- Answer: Methyl Mercury poisoning.
Creating: Planting trees hypothesis.
- Answer: Trees are "carbon sinks"; they absorb CO2 for photosynthesis, reducing the atmospheric concentration.
Designing: 3Rs visual.
- Answer: [Reduce: Use less. Reuse: Use again. Recycle: Process into new things].
Application: Organic Farming.
- Answer: Uses natural fertilizers (compost) and biopesticides, preventing the accumulation of toxic chemicals in the soil.
Critical Thinking: Bio-indicators (Lichens).
- Answer: Lichens are highly sensitive to SO2; their absence in an area indicates high air pollution.
Analysis: Carbon Footprint.
- Answer: The total amount of greenhouse gases produced by an individual's actions (transport, food, energy use).

Section E: Advanced Competency

Scenario: Odd-Even rule.
- Answer: Reduces the number of vehicles on the road, lowering the emission of pollutants during severe smog episodes.
Designing: E-Waste Management poster.
- Answer: "Don't trash your tech. Dispose of electronics at authorized collection centers."
Application: Montreal Protocol.
- Answer: An international treaty signed to phase out the production of ozone-depleting substances.
Creating: Global Warming quiz.
- Answer: [True: Rising sea levels will flood coastal cities. True: Glaciers are melting at record rates].
Case Study: Thermal Pollution.
- Answer: Warm water holds less dissolved Oxygen, which can cause mass death of fish and disrupt breeding.
Sustainable Development.
- Answer: Development that meets the needs of the present without compromising the ability of future generations to meet their own needs.
Critical Thinking: Electric vehicles (EVs).
- Answer: EVs reduce tailpipe emissions, but the electricity must come from renewable sources, and battery mining/disposal must be managed.
Analysis: Thermal vs Hydro power.
- Answer: Thermal: High air pollution (CO2/SO2). Hydro: No air pollution but causes habitat destruction and displacement of people.
Designing: Global Temp graph.
- Answer: Shows a "hockey stick" curve with a sharp rise starting from the Industrial Revolution.
Creating: Ocean Cleanup device.
- Answer: [E.g., A floating barrier with a screen that collects plastic using ocean currents].

Section A: Case-Based Questions

Case Study 1: Lake covered with algae, fish dying, village runoff.

Identify the phenomenon.

Answer: Eutrophication (followed by Algal Bloom).

Nutrients responsible.

Answer: Nitrates and Phosphates (from detergents and fertilizers).

Designing: Restoration methods.

Answer: Diverting sewage away from the lake, and "Bioremediation" (using plants/microbes to absorb excess nutrients).

Analysis: Why are fish dying?

Answer: Algae die and are decomposed by bacteria, which use up all the dissolved Oxygen in the water, causing fish to suffocate.

Define "BOD".

Answer: Biological Oxygen Demand - the amount of dissolved oxygen needed by aerobic biological organisms to break down organic material in a water sample.

Case Study 2: City smog in winter, eye irritation. 6. Identify the pollution.

Answer: Smog (Smoke + Fog).

What is "Photochemical Smog"?

Answer: Smog produced when sunlight reacts with nitrogen oxides and volatile organic compounds (from car exhausts).

Creating: Health advisory.

Answer: "Wear N95 masks, avoid outdoor exercise in the morning, use air purifiers, and keep hydrated."

Critical Thinking: Stubble burning contribution.

Answer: Releases massive amounts of smoke and particulate matter (PM) which get trapped in the cold, still air of winter (Temperature Inversion).

PM 2.5 and PM 10 role.

Answer: These fine particles can penetrate deep into the lungs and even enter the bloodstream, causing asthma, bronchitis, and heart disease.

Section B: Assertion-Reasoning Questions

Directions: (a) Both A/R true, R explains A; (b) Both true, R doesn't explain A; (c) A true, R false; (d) A false, R true.

Assertion (A): Taj Mahal is turning yellow. Reason (R): Acid rain reacts with marble.

Answer: (a) Both A and R are true and R is the correct explanation.

Assertion (A): Ozone in stratosphere is "Good Ozone". Reason (R): Shields from UV radiation.

Answer: (a) Both A and R are true and R is the correct explanation.

Assertion (A): Plastic bags should be banned. Reason (R): They are non-biodegradable.

Answer: (a) Both A and R are true and R is the correct explanation.

Assertion (A): CO2 is a Green House Gas. Reason (R): It traps infrared radiation.

Answer: (a) Both A and R are true and R is the correct explanation.

Assertion (A): Noise pollution can cause hypertension. Reason (R): Loud noise increases adrenaline.

Answer: (a) Both A and R are true and R is the correct explanation.

Section C: Creating and Designing (Application & Analysis)

Designing: Rainwater Harvesting.

Answer: [Roof -> Pipes -> Filter -> Storage Tank -> Groundwater Recharge].

Creating: Slogan.

Answer: "Clean India, Green India."

Analysis: Biodegradable vs Non-biodegradable.

Answer: Biodegradable: Can be broken down by microbes (Paper, Food). Non-biodegradable: Cannot be broken down (Plastic, Glass, DDT).

Designing: Pollutants table.

Answer: [CO: Car exhaust (suffocation). SO2: Factories (acid rain). DDT: Pesticide (Biomagnification). Mercury: Industrial waste (Minamata disease)].

Visualisation: Greenhouse Effect.

Answer: [Description: Solar rays enter, but heat rays cannot escape through the layer of GHGs].

Application: Why ban CFCs?

Answer: They release chlorine atoms in the stratosphere which break down Ozone ( $O_3$ ) molecules into Oxygen ( $O_2$ ), thinning the ozone layer.

Creating: Waste-to-Wealth.

Answer: Making paper mache bowls or recycling into cardboard.

Analysis: Biomagnification of DDT.

Answer: DDT concentration increases at each trophic level because it is not metabolized; it leads to thin eggshells in birds of prey.

Designing: Reduce Noise Pollution.

Answer: Using silencers in machines, "No Honking" zones near hospitals, and planting trees (Green Muffler).

Creating: Speech on Single-Use Plastic.

Answer: [Focus on ocean pollution, death of cattle/turtles, and microplastics in food].

Section D: Competency & Critical Thinking

Acid Rain.

Answer: Rain containing nitric and sulfuric acids. pH below 5.6.

Scenario: Nuclear radiation risks.

Answer: DNA damage leading to genetic mutations, leukemia, and other cancers.

Critical Thinking: Is Greenhouse Effect entirely bad?

Answer: No, without it, the Earth's average temperature would be -18°C, too cold for most life. The problem is the enhanced effect.

Application: Scrubber/Precipitator.

Answer: Used in chimney stacks to remove gases (Scrubber) or dust particles (Precipitator) from industrial smoke.

Pollutant vs Contaminant.

Answer: Pollutant: Harmful substance that reduces quality of environment. Contaminant: Substance in the wrong place but not necessarily harmful yet.

Diagram Based: GHG pie chart.

Answer: CO2 accounts for approx 60% of the enhanced greenhouse effect.

Oil Spills impact.

Answer: Coats feathers of birds (hypothermia) and prevents gas exchange for marine life.

Analysis: Unleaded petrol.

Answer: Lead is a neurotoxin; removing it prevents lead poisoning and allows the use of catalytic converters in cars.

Competency: BS-VI norms.

Answer: Stringent standards for vehicle tailpipe emissions (CO, HC, NOx, and PM).

Case: Minamata disease.

Answer: Methyl Mercury poisoning.

Creating: Planting trees hypothesis.

Answer: Trees are "carbon sinks"; they absorb CO2 for photosynthesis, reducing the atmospheric concentration.

Designing: 3Rs visual.

Answer: [Reduce: Use less. Reuse: Use again. Recycle: Process into new things].

Application: Organic Farming.

Answer: Uses natural fertilizers (compost) and biopesticides, preventing the accumulation of toxic chemicals in the soil.

Critical Thinking: Bio-indicators (Lichens).

Answer: Lichens are highly sensitive to SO2; their absence in an area indicates high air pollution.

Analysis: Carbon Footprint.

Answer: The total amount of greenhouse gases produced by an individual's actions (transport, food, energy use).

Section E: Advanced Competency

Scenario: Odd-Even rule.

Answer: Reduces the number of vehicles on the road, lowering the emission of pollutants during severe smog episodes.

Designing: E-Waste Management poster.

Answer: "Don't trash your tech. Dispose of electronics at authorized collection centers."

Application: Montreal Protocol.

Answer: An international treaty signed to phase out the production of ozone-depleting substances.

Creating: Global Warming quiz.

Answer: [True: Rising sea levels will flood coastal cities. True: Glaciers are melting at record rates].

Case Study: Thermal Pollution.

Answer: Warm water holds less dissolved Oxygen, which can cause mass death of fish and disrupt breeding.

Sustainable Development.

Answer: Development that meets the needs of the present without compromising the ability of future generations to meet their own needs.

Critical Thinking: Electric vehicles (EVs).

Answer: EVs reduce tailpipe emissions, but the electricity must come from renewable sources, and battery mining/disposal must be managed.

Analysis: Thermal vs Hydro power.

Answer: Thermal: High air pollution (CO2/SO2). Hydro: No air pollution but causes habitat destruction and displacement of people.

Designing: Global Temp graph.

Answer: Shows a "hockey stick" curve with a sharp rise starting from the Industrial Revolution.

Creating: Ocean Cleanup device.

Answer: [E.g., A floating barrier with a screen that collects plastic using ocean currents].

Pollution

Pollution - Competency-Based Question Bank (with Answers)

Section A: Case-Based Questions

Section B: Assertion-Reasoning Questions

Section C: Creating and Designing (Application & Analysis)

Section D: Competency & Critical Thinking

Section E: Advanced Competency

On this page

Pollution

Pollution - Competency-Based Question Bank (with Answers)

Section A: Case-Based Questions

Section B: Assertion-Reasoning Questions

Section C: Creating and Designing (Application & Analysis)

Section D: Competency & Critical Thinking

Section E: Advanced Competency

On this page