Science · Class 8
Pollution of Air and Water
Causes and control of air and water pollution; Ganga action plan.
4 sections15–25 min read6 MCQs · 2 examples
Chapter Overview
Pollution harms health and environment. This chapter covers pollutants, greenhouse effect, acid rain, water pollutants, Ganga action plan, and individual actions to reduce pollution.
Air Pollution
- Pollutants: CO, SO₂, NO₂, particulate matter, CFCs
- Greenhouse effect: CO₂ traps heat — global warming
- Acid rain: SO₂/NO₂ dissolve in rain — damages monuments, aquatic life
Water Pollution
- Sewage, industrial waste, fertiliser runoff, oil spills
- Eutrophication: excess nutrients → algal bloom → fish death
- Ganga Action Plan: clean major river
Prevention
- CNG vehicles, catalytic converters, tree plantation
- Treat industrial effluent; no plastic in rivers
- 3 R's; water treatment before discharge
Solved Examples
Step-by-step solutions — read each step before checking the final answer.
Greenhouse effect
How does CO₂ cause global warming?
- 1CO₂ traps infrared radiation from Earth
- 2Heat cannot escape easily
- 3Average temperature rises
Answer
Traps heat in atmosphere
Water pollutant
How do fertilisers pollute water?
- 1Wash into rivers from fields
- 2Excess nutrients cause algal bloom
- 3Decomposing algae use up oxygen — fish die
Answer
Eutrophication from nutrient runoff
Key Points to Remember
- ✓ CFCs deplete ozone layer
- ✓ Marble (Taj Mahal) damaged by acid rain
- ✓ Potable water must be treated
Exam Tips
- • List major air and water pollutants
- • Explain acid rain formation
- • Suggest ways to reduce pollution at home
Practice MCQs — Pollution of Air and Water
Test your understanding with topic-wise multiple choice questions. Explanations appear after each answer.
Question 1 of 6Score: 0/0
Major greenhouse gas is: