1. Impact of waste accumulation
- Spoilage of landscape: roadside heaps; giant dumps such as Ghazipur (Delhi) and Deonar (Mumbai); littered riverbanks and beaches.
- Pollution: leachate pollutes groundwater and streams; plastic clogs drains and worsens floods; burning garbage and methane fires pollute air; plastics and chemicals poison soil.
- Health hazards: flies, mosquitoes and rats spread cholera, typhoid, dengue and malaria; smoke causes breathing problems; waste pickers face injury and infection; cattle eat plastic.
| Effect | Example |
|---|---|
| Landscape | Garbage hills on city edges |
| Pollution | Leachate in wells; clogged drains |
| Health | Mosquito-borne and water-borne disease |
Key terms
- Leachate
The polluted liquid formed when rainwater seeps through waste.
2. Need for waste management
- Urban population, incomes and packaging are rising, so waste is increasing.
- Land for dumps near cities is scarce and costly.
- Protects public health and prevents epidemics.
- Protects water, soil and air.
- Recovers resources (compost, paper, metals, plastics) and creates jobs.
- Swachh Bharat Mission (2014) and the Solid Waste Management Rules, 2016 require segregation at source (as of the early 2020s).
| Reason | Key word |
|---|---|
| More waste | Urban growth |
| Health | Epidemics |
| Resources | Recycling, compost |
Key terms
- Municipal solid waste
The everyday solid waste collected from homes, shops, offices and streets of a town.
3. Key environmental terms
| Term | Meaning | One cause | One effect |
|---|---|---|---|
| Global warming | Rise in Earth’s average temperature as greenhouse gases trap heat | Burning fossil fuels; methane from landfills | Melting glaciers; rising sea level |
| Acid rain | Rain made acidic by sulphur and nitrogen oxides | Smoke from power stations, factories, vehicles | Corrodes marble monuments; kills fish in lakes |
| Eutrophication | Over-enrichment of water with nutrients | Fertiliser run-off, sewage, detergents | Algal bloom; oxygen loss; fish die |
| Biomagnification | Rise in concentration of persistent poisons up a food chain | DDT, mercury in water | Thin eggshells in birds of prey; poisoning |
| Thermal pollution | Harmful heating of water bodies | Hot water from power stations, industries | Less dissolved oxygen; fish die |
| Term | Key substance |
|---|---|
| Acid rain | Sulphur dioxide |
| Eutrophication | Phosphates, nitrates |
| Biomagnification | DDT, mercury |
Key terms
- Greenhouse gas
A gas such as carbon dioxide or methane that traps heat in the atmosphere.
- Algal bloom
A rapid, dense growth of algae in nutrient-rich water.
4. Segregation and dumping
- Segregation at source: wet (biodegradable) — green bin; dry (paper, plastic, glass, metal) — blue bin; domestic hazardous (batteries, bulbs, medicines, paint) — separate.
- Why first: enables composting and recycling; isolates hazardous items; reduces landfill; protects waste workers; cheaper handling.
- Open dumping: cheap but causes leachate, methane fires, smell, flies, rats; wastes land.
- Sanitary landfill: clay and plastic liner; leachate collection and treatment; daily soil cover; gas vents; final clay cap with soil and grass; only inert rejects should go there.
| Bin | Contents |
|---|---|
| Green | Wet, biodegradable |
| Blue | Dry, recyclable |
| Separate | Domestic hazardous |
Key terms
- Segregation at source
Separating waste into wet, dry and hazardous kinds where it is produced.
- Sanitary landfill
An engineered, lined and covered site for the safe burial of waste that cannot be recovered.
5. Composting
- Composting: aerobic decomposition of biodegradable waste by microbes into humus-rich manure; pit or bin; layers of kitchen waste, dry leaves and soil; kept moist and turned; ready in about six to eight weeks.
- Vermicomposting: earthworms eat the waste and produce nutrient-rich castings.
- Landfill vs composting: landfill uses large land for decades, produces methane and leachate, gives no product; composting needs little land, produces little methane, gives manure, but needs segregated waste and care.
| Feature | Landfill | Compost |
|---|---|---|
| Land | Large | Small |
| Methane | Much | Little |
| Product | None | Manure |
Key terms
- Composting
Turning biodegradable waste into manure by the action of microbes in the presence of air.
- Vermicomposting
Composting with the help of earthworms.
6. Reduce, reuse, recycle
- Need: saves resources and energy; less waste to dumps; less pollution; jobs in recycling.
- Reduce: cloth bags, refillable bottles, refuse single-use plastic (several items banned from July 2022, as of the early 2020s), avoid food waste.
- Reuse: glass jars, both sides of paper, repair, pass on books and uniforms.
- Recycle: paper, cardboard, metal, glass, plastic to recyclers or kabadiwala; e-waste to authorised collectors.
- Good practice: Indore (segregation, composting), Alappuzha (home composting), Pune (waste-picker cooperative).
- Share of a waste type = its weight ÷ total weight × 100.
| R | Example |
|---|---|
| Reduce | Cloth bag |
| Reuse | Glass jar |
| Recycle | Old newspapers to recycler |
Key terms
- Recycling
Processing used materials so that they can be made into new products.
Exam tips
Common mistakes
- Calling composting anaerobic (it needs air; landfills rot without air).
- Saying acid rain is caused by carbon monoxide.
- Writing that eutrophication adds oxygen.
- Putting batteries or medicines into the wet bin.
How marks are usually awarded
- Effects (1 mark each): landscape, pollution, health, each with an example.
- Key terms (2 marks): definition plus one cause and one effect.
- Methods (3 marks): segregation, landfill features or composting steps in order.
- 3Rs (1 mark each): practical, distinct examples.