CBSE Class 6 General Knowledge

Unit 5: Environment & Ecology

Lesson: Pollution – Causes and Effects

📘 Study Module: Pollution – Causes and Effects

1. Introduction

Pollution is one of the major environmental problems faced by the world today. It occurs when harmful substances enter the environment and cause damage to living beings and natural resources. Pollution affects air, water, land, and health.

2. Meaning of Pollution

Pollution is the contamination of the environment by harmful substances called pollutants. These pollutants may be solid, liquid, or gaseous and are mainly caused by human activities.

3. Types of Pollution

The main types of pollution are:

• Air Pollution
• Water Pollution
• Land (Soil) Pollution
• Noise Pollution

Each type affects the environment in different ways.

4. Air Pollution

Air pollution is caused by smoke, gases, and dust released into the air. Vehicles, factories, and burning of fuels are major causes. It leads to breathing problems and global warming.

5. Water Pollution

Water pollution occurs when harmful substances are released into rivers, lakes, and seas. Industrial waste, sewage, and oil spills pollute water. Polluted water causes diseases and harms aquatic life.

6. Land Pollution

Land pollution is caused by dumping garbage, plastics, and chemicals on land. Excessive use of pesticides also pollutes soil. It reduces soil fertility and affects plant growth.

7. Noise Pollution

Noise pollution is caused by loud sounds from vehicles, machines, and loudspeakers. Continuous noise affects hearing and causes stress. It also disturbs animals.

8. Effects of Pollution

Pollution harms human health, animals, plants, and natural resources. It causes diseases, climate change, and loss of biodiversity. Pollution also reduces the quality of life.

9. Control of Pollution

Pollution can be controlled by reducing waste, recycling materials, using clean energy, and spreading awareness. Protecting the environment is everyone’s responsibility.

📝 Questions and Answers

A. Short Answer Questions

(One sentence each)

1. What is pollution?
   Answer: Pollution is the contamination of the environment by harmful substances.
2. What are pollutants?
   Answer: Pollutants are harmful substances that cause pollution.
3. Name any two types of pollution.
   Answer: Air pollution and water pollution.
4. What causes air pollution?
   Answer: Smoke from vehicles and factories causes air pollution.
5. What causes water pollution?
   Answer: Industrial waste and sewage cause water pollution.
6. What is land pollution?
   Answer: Land pollution is the contamination of soil by waste and chemicals.
7. What causes noise pollution?
   Answer: Loud sounds from vehicles and machines cause noise pollution.
8. Name one effect of pollution.
   Answer: Pollution causes diseases.
9. Which pollution affects breathing?
   Answer: Air pollution affects breathing.
10. Why should pollution be controlled?
    Answer: Pollution should be controlled to protect health and the environment.

B. Long Answer Questions

(3–5 sentences each)

11. Explain pollution in your own words.
    Answer: Pollution is the presence of harmful substances in the environment. These substances damage air, water, and land. Pollution mainly occurs due to human activities. It affects all living beings.
12. Describe air pollution and its causes.
    Answer: Air pollution is caused by smoke and harmful gases. Vehicles and factories release pollutants into the air. Burning fuels also causes air pollution. It leads to breathing problems.
13. Explain water pollution and its effects.
    Answer: Water pollution occurs when waste enters water bodies. It makes water unsafe for drinking. Aquatic plants and animals are harmed. It causes water-borne diseases.
14. What is land pollution and how does it occur?
    Answer: Land pollution is caused by dumping waste on land. Plastic waste and chemicals pollute soil. Excessive use of pesticides also causes land pollution. It reduces soil fertility.
15. Explain noise pollution.
    Answer: Noise pollution is caused by loud sounds. Vehicles, machines, and loudspeakers create noise. It affects hearing and causes stress. It also disturbs animals.
16. How does pollution affect human health?
    Answer: Pollution causes respiratory diseases. Polluted water spreads infections. Noise causes stress and hearing loss. Pollution lowers quality of life.
17. How does pollution affect the environment?
    Answer: Pollution harms plants and animals. It causes climate change. Soil fertility decreases. Ecosystems lose balance.
18. What are the causes of pollution?
    Answer: Industrial activities cause pollution. Vehicles release smoke. Improper waste disposal increases pollution. Human activities are the main cause.
19. How can pollution be reduced?
    Answer: Pollution can be reduced by recycling waste. Using clean energy helps. Planting trees reduces air pollution. Awareness is important.
20. Why is pollution a serious problem?
    Answer: Pollution affects health and nature. It destroys ecosystems. Natural resources get damaged. Pollution threatens future life.

🧠 Multiple Choice Questions (MCQs)

(With Answers and Detailed Explanations)

1. Pollution means ______.
   a) cleanliness
   b) contamination
   c) recycling
   d) conservation
   Answer: b) contamination
   Explanation: Pollution is contamination of environment.
2. Harmful substances that cause pollution are called ______.
   a) nutrients
   b) pollutants
   c) minerals
   d) resources
   Answer: b) pollutants
   Explanation: Pollutants cause pollution.
3. Smoke from vehicles causes ______ pollution.
   a) water
   b) land
   c) air
   d) noise
   Answer: c) air
   Explanation: Smoke pollutes air.
4. Which pollution affects rivers and lakes?
   a) Air
   b) Noise
   c) Water
   d) Land
   Answer: c) Water
   Explanation: Waste pollutes water bodies.
5. Dumping garbage causes ______ pollution.
   a) air
   b) water
   c) land
   d) noise
   Answer: c) land
   Explanation: Garbage pollutes soil.
6. Loudspeakers cause ______ pollution.
   a) air
   b) noise
   c) water
   d) land
   Answer: b) noise
   Explanation: Loud sounds cause noise pollution.
7. Which pollution affects breathing?
   a) Water
   b) Noise
   c) Air
   d) Land
   Answer: c) Air
   Explanation: Polluted air affects lungs.
8. Industrial waste mainly causes ______ pollution.
   a) air only
   b) water only
   c) water and land
   d) noise
   Answer: c) water and land
   Explanation: Waste enters water and soil.
9. Which of the following is an effect of pollution?
   a) Good health
   b) Clean air
   c) Diseases
   d) Fresh water
   Answer: c) Diseases
   Explanation: Pollution causes illness.
10. Which pollution affects hearing?
    a) Air
    b) Water
    c) Noise
    d) Land
    Answer: c) Noise
    Explanation: Loud sounds damage ears.
11. Plastic waste mainly causes ______ pollution.
    a) air
    b) land
    c) noise
    d) water
    Answer: b) land
    Explanation: Plastic pollutes soil.
12. Which activity increases air pollution?
    a) Planting trees
    b) Recycling
    c) Burning fuel
    d) Saving energy
    Answer: c) Burning fuel
    Explanation: Burning releases smoke.
13. Which pollution harms aquatic life?
    a) Air
    b) Water
    c) Noise
    d) Land
    Answer: b) Water
    Explanation: Polluted water kills fish.
14. Which gas is released by vehicles?
    a) Oxygen
    b) Carbon dioxide
    c) Nitrogen
    d) Hydrogen
    Answer: b) Carbon dioxide
    Explanation: Vehicles emit CO₂.
15. Which pollution is caused by factories?
    a) Only noise
    b) Only air
    c) Air and water
    d) Only land
    Answer: c) Air and water
    Explanation: Factories release smoke and waste.
16. Which pollution affects soil fertility?
    a) Air
    b) Water
    c) Land
    d) Noise
    Answer: c) Land
    Explanation: Chemicals reduce soil quality.
17. Which action helps reduce pollution?
    a) Burning waste
    b) Cutting trees
    c) Recycling
    d) Using plastic
    Answer: c) Recycling
    Explanation: Recycling reduces waste.
18. Pollution affects ______.
    a) humans only
    b) animals only
    c) plants only
    d) all living beings
    Answer: d) all living beings
    Explanation: Pollution harms all life.
19. Noise pollution can cause ______.
    a) happiness
    b) hearing loss
    c) rainfall
    d) growth
    Answer: b) hearing loss
    Explanation: Loud noise damages ears.
20. Pollution control is important to ______.
    a) increase waste
    b) destroy nature
    c) protect environment
    d) stop development
    Answer: c) protect environment
    Explanation: Control keeps nature safe.

✅ End of Lesson

Prepared strictly in accordance with the NCERT syllabus and CBSE Class 6 examination standards.