Chapter 16: Environmental Issues

Q1. What is air pollution? What are its major causes?

Solution

Causes: (1) Vehicle emissions (CO, NOx) (2) Industrial pollution (SO₂, particulate matter) (3) Burning fossil fuels (4) Deforestation (5) Agricultural activities
Effects: Smog, acid rain, respiratory diseases, global warming

Q2. What is smog? What are its types?

Solution

Classical smog: SO₂ + particulate + fog (London type, reducing)
Photochemical smog: NOx + hydrocarbons + sunlight (Los Angeles type, oxidizing)
Health effects: Breathing difficulties, asthma, lung cancer, eye irritation

Q3. What is acid rain? What are its effects?

Solution

Caused by: SO₂ and NOx reacting with water vapour
Effects: (1) Damages buildings and monuments (2) Acidifies lakes and streams (3) Kills aquatic organisms (4) Damages vegetation (5) Corrodes metals

Q4. What are the water pollution types? Name major pollutants.

Solution

Types: (1) Biomedical waste (2) Eutrophication (3) Industrial effluents (4) Sewage
Pollutants: Pathogens, Organic matter, Nutrients (N, P), Heavy metals, Plastics

Q5. What is eutrophication? How does it affect aquatic ecosystems?

Solution

Process: (1) Nutrient enrichment (N, P) from fertilizers/sewage (2) Algal bloom (3) Algae die, decomposed by bacteria (4) O₂ depleted (hypoxia) (5) Fish and organisms die (dead zone)

Q6. What is ozone depletion? What are its causes and effects?

Solution

Causes: CFCs, halons, methyl bromide (refrigerants, aerosols)
Effects: (1) Increased UV radiation (2) Skin cancer (3) Cataracts (4) Damages crops and marine phytoplankton (5) Weakens immune system
Solution: Montreal Protocol (1987) - phase out CFCs

Q7. What is the greenhouse effect? What are greenhouse gases?

Solution

Gases: CO₂ (major), CH₄, N₂O, CFCs, water vapour
Mechanism: Solar radiation enters atmosphere, earth radiates infrared, greenhouse gases trap infrared, warming earth
Effects: Global warming, climate change, melting glaciers, sea level rise

Q8. What are the effects of global warming?

Solution

1. Melting of glaciers and polar ice caps
2. Rise in sea level (flooding of coastal areas)
3. Changes in precipitation patterns
4. Extreme weather events
5. Shifts in species distribution
6. Agricultural productivity changes

Q9. What is deforestation? What are its consequences?

Solution

Consequences: (1) Loss of biodiversity (2) Increased CO₂ levels (3) Soil erosion (4) Floods and droughts (5) Loss of livelihood for tribal communities
Example: Deforestation in Narmada for Sardar Sarovar Dam

Q10. What is the case study of Delhi CNG?

Solution

Background: (1) Supreme Court mandated CNG in public transport (2001) (2) Diesel buses caused severe air pollution (3) CNG (Compressed Natural Gas) is cleaner
Results: (1) Reduced CO and particulate matter (2) Improved air quality (3) Successfully implemented despite initial resistance

Q11. What is solid waste management? What are its methods?

Solution

Methods: (1) Collection and transportation (2) Disposal - sanitary landfills, open dumping (3) Recycling (4) Composting (5) Incineration (6) Reduction at source
3R principle: Reduce, Reuse, Recycle

Q12. What are the steps in sewage treatment?

Solution

Primary: Physical - screening, sedimentation, skimming
Secondary: Biological - activated sludge process, trickling filters
Tertiary: Chemical - chlorination, UV treatment, reverse osmosis

Q13. What is e-waste? How should it be managed?

Solution

Sources: Old computers, phones, TVs, batteries
Dangers: Contains lead, mercury, cadmium, chromium
Management: (1) Recycling (2) Proper disposal (3) Extended producer responsibility (4) Informal recycling should be avoided (health hazards)

Q14. What are the government initiatives for environmental protection in India?

Solution

1. Environment Protection Act, 1986
2. Air (Prevention and Control) Act, 1981
3. Water (Prevention and Control) Act, 1974
4. National Green Tribunal (NGT)
5. National Afforestation Programme
6. Swachh Bharat Mission (solid waste)

Q15. What is the role of individuals in preventing environmental pollution?

Solution

1. Reduce, Reuse, Recycle (3R)
2. Use public transport, carpooling
3. Conserve water and electricity
4. Plant trees, avoid deforestation
5. Proper waste disposal
6. Use eco-friendly products
7. Support environmental awareness

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