Pollution of Air and Water – Very Short Answer Type Questions
Class 8
Science
NCERT – Chapter 18
Strictly Based on NCERT Syllabus
CBSE Class 8 Science – Chapter 18: Pollution of Air and Water
Topic-wise Very Short Answer Type Questions with answers for quick NCERT-based revision.
Useful For: Class Tests • Periodic Assessments • Half-Yearly & Annual Exams • CBSE Class 8 Board Exam Standard Preparation
These Very Short Answer Type Questions are part of the
CBSE Class 8 Science – Chapter Wise Study Materials Based on NCERT.
All questions are designed strictly as per the NCERT textbook for
Chapter 18: Pollution of Air and Water, making them ideal for quick revision
and CBSE Class 8 board exams standard practice.
Very Short Answer Type Questions – Topic-wise
Topic 1: Basics of Pollution and Environment
Questions 1–6
Q1. What is pollution?
Ans: Pollution is any undesirable change in the environment that harms living beings.
Q2. What is a pollutant?
Ans: A pollutant is any substance that causes pollution when added to air, water or soil.
Q3. Name the two main types of pollution discussed in this chapter.
Ans: Air pollution and water pollution.
Q4. What is meant by environment?
Ans: Environment is the surroundings that include air, water, soil, plants, animals and humans.
Q5. Name any two human activities that cause both air and water pollution.
Ans: Burning of fuels and discharge of untreated industrial waste.
Q6. Why is pollution harmful?
Ans: Pollution is harmful because it affects health, damages property and disturbs balance in nature.
Topic 2: Air Pollution – Pollutants and Sources
Questions 7–16
Q7. What is air pollution?
Ans: Air pollution is contamination of air by harmful substances beyond a safe limit.
Q8. Name two primary air pollutants released from vehicles.
Ans: Carbon monoxide (CO) and nitrogen oxides (NOx).
Q9. Which gas is produced due to incomplete combustion of fuels?
Ans: Carbon monoxide (CO).
Q10. Name any two types of industries that cause air pollution.
Ans: Thermal power plants and cement factories.
Q11. What do you mean by Suspended Particulate Matter (SPM)?
Ans: SPM are tiny solid or liquid particles like dust, smoke and soot present in air.
Q12. Name any two greenhouse gases.
Ans: Carbon dioxide (CO₂) and methane (CH₄).
Q13. Which gas is mainly responsible for the increase in global warming?
Ans: Carbon dioxide (CO₂).
Q14. Which gas is released when coal containing sulphur is burnt?
Ans: Sulphur dioxide (SO₂).
Q15. Which fuel is called a clean fuel for vehicles in many Indian cities?
Ans: Compressed Natural Gas (CNG).
Q16. What is meant by a chimney or stack in a factory?
Ans: It is a tall structure that releases smoke and gases high into the atmosphere.
Topic 3: Smog, Acid Rain, Global Warming and Ozone Layer
Questions 17–24
Q17. What is smog?
Ans: Smog is a thick fog-like layer formed when smoke mixes with fog in the air.
Q18. Smog is formed from which two words?
Ans: Smoke and fog.
Q19. What is acid rain?
Ans: Acid rain is rainwater that contains acids formed from gases like SO₂ and NOx.
Q20. Name any two acids present in acid rain.
Ans: Sulphuric acid and nitric acid.
Q21. How does acid rain affect monuments like the Taj Mahal?
Ans: Acid rain corrodes marble and damages the surface of monuments.
Q22. What is global warming?
Ans: Global warming is the gradual increase in the average temperature of the Earth.
Q23. What is greenhouse effect?
Ans: Greenhouse effect is the trapping of heat by greenhouse gases in the atmosphere.
Q24. Which protective layer in the atmosphere absorbs harmful UV rays?
Ans: The ozone layer in the stratosphere.
Topic 4: Control of Air Pollution
Questions 25–30
Q25. Mention any two ways to reduce air pollution from vehicles.
Ans: Using CNG and maintaining vehicles regularly.
Q26. How does planting trees help in controlling air pollution?
Ans: Trees absorb carbon dioxide and release oxygen, improving air quality.
Q27. Why should we prefer public transport instead of private vehicles?
Ans: Because it reduces the number of vehicles and hence reduces air pollution.
Q28. What is the role of filters in factory chimneys?
Ans: Filters trap harmful particles before smoke is released into the air.
Q29. Name the Act passed by the Government of India to control air pollution.
Ans: The Air (Prevention and Control of Pollution) Act, 1981.
Q30. What is Air Quality Index (AQI)?
Ans: AQI is a number that shows how clean or polluted the air in a particular area is.
Topic 5: Water Pollution – Sources and Effects
Questions 31–40
Q31. What is water pollution?
Ans: Water pollution is contamination of water bodies by harmful substances.
Q32. Name any two water bodies that often get polluted in India.
Ans: Rivers Ganga and Yamuna.
Q33. Name two main sources of water pollution in cities.
Ans: Discharge of sewage and industrial effluents.
Q34. How do fertilisers cause water pollution?
Ans: Excess fertilisers are washed by rain into water bodies, adding harmful chemicals.
Q35. What are industrial effluents?
Ans: Industrial effluents are liquid wastes released from factories into water bodies.
Q36. What is eutrophication?
Ans: Eutrophication is nutrient enrichment of water causing excessive growth of algae.
Q37. What is an algal bloom?
Ans: Algal bloom is a thick growth of algae forming a green layer on the water surface.
Q38. How does water pollution affect aquatic animals?
Ans: It reduces dissolved oxygen and can kill fish and other aquatic animals.
Q39. Why is it unsafe to discharge untreated sewage into rivers?
Ans: Because it spreads diseases and makes river water unfit for use.
Q40. Name any two water-borne diseases caused by polluted water.
Ans: Cholera and typhoid.
Topic 6: Potable Water and Purification Methods
Questions 41–46
Q41. What is potable water?
Ans: Potable water is water that is safe for drinking.
Q42. State any one characteristic of potable water.
Ans: It should be free from harmful germs.
Q43. How does boiling make water safe for drinking?
Ans: Boiling kills most of the disease-causing germs present in water.
Q44. Name any one chemical used to disinfect drinking water.
Ans: Chlorine.
Q45. What is chlorination?
Ans: Chlorination is the process of adding chlorine to water to kill germs.
Q46. Expand RO as used in water purifiers.
Ans: RO stands for Reverse Osmosis.
Topic 7: Sewage Treatment and Prevention of Pollution
Questions 47–50
Q47. What is sewage?
Ans: Sewage is wastewater from homes, offices and industries containing human and other wastes.
Q48. What is a Sewage Treatment Plant (STP)?
Ans: An STP is a plant where sewage is treated to remove pollutants before disposal.
Q49. Mention one way you can help reduce water pollution at home.
Ans: By not throwing oils, chemicals or plastics into drains or water bodies.
Q50. Why is public awareness important for controlling pollution?
Ans: Because pollution can be reduced only when people understand its harms and change their habits.