Chapter 1 — Environment

Meaning of Environment
The environment means everything that surrounds us — living organisms (plants, animals, humans) and non-living things (air, water, soil, climate). It includes the natural world and those parts that have been changed by humans. The environment provides materials, energy and conditions needed for life.

Two broad types of components

• Abiotic (non-living) components: These are physical and chemical parts of the environment that do not have life. Main abiotic components are:
• Atmosphere: The layer of gases around the Earth (air) — provides oxygen, carbon dioxide, and protects from harmful solar radiation.
• Hydrosphere: All water on Earth — oceans, rivers, lakes, groundwater, glaciers — important for drinking, irrigation and industry.
• Lithosphere/Geosphere: The solid Earth — rocks, soil, minerals and landforms — supports plant growth and provides raw materials.
• Biotic (living) components: All living organisms — plants, animals, fungi, bacteria. These interact with abiotic parts and with each other (food chains, habitats).
• Humans and human-made environment (Anthroposphere): Human settlements, roads, farms, industry and all modifications we make. Humans both depend on and change natural components.

Interactions and Processes
The components are linked by continuous cycles and interactions: the water cycle (evaporation, condensation, precipitation), the carbon and oxygen cycles, energy flow from the Sun through producers (plants) to consumers and decomposers. These interactions maintain balance; disruption (pollution, deforestation) causes environmental problems.

Why it matters
Understanding components helps us protect resources: clean air and water, healthy soils, biodiversity and stable climate. Each component supports life directly or indirectly, so conserving them keeps the environment healthy.

What is the Atmosphere?

The atmosphere is the layer of gases that surrounds the Earth. It is held close to the planet by gravity and makes life possible by providing air to breathe, protecting us from harmful solar radiation, and helping regulate temperature.

Composition

• Major gases (by volume): Nitrogen (N2) ~78%, Oxygen (O2) ~21%, Argon (Ar) ~0.93%, Carbon dioxide (CO2) ~0.04% (variable).
• Other components: Water vapour (variable, 0–4%), dust, pollen, aerosols and trace gases.

Structure — Layers of the Atmosphere

• Troposphere (surface to ~8–15 km): Weather occurs here; temperature generally decreases with height.
• Stratosphere (~15–50 km): Contains the ozone layer; temperature rises with height because ozone absorbs UV radiation.
• Mesosphere (~50–85 km): Temperature decreases with height; meteors burn here.
• Thermosphere (~85–600+ km): Temperature increases with height; auroras occur here and satellites orbit in the upper parts.
• Exosphere (above ~600 km): Thin outermost layer gradually blending into space.

Important Functions of the Atmosphere

• Provides oxygen and other gases necessary for life.
• Protects Earth by absorbing ultraviolet (UV) radiation (ozone layer) and burning up many meteors.
• Helps maintain a livable temperature through the greenhouse effect.
• Transports water and energy — drives weather and climate (winds, clouds, rain).

Key Processes

• Weather vs Climate: Weather is short-term state of the atmosphere (rain, wind, temperature). Climate is long-term average of weather in a region.
• Greenhouse effect: Some gases (CO2, CH4, water vapour) trap heat and keep Earth warm. Excess greenhouse gases cause global warming.
• Ozone layer: Ozone (O3) in the stratosphere absorbs harmful UV rays. Depletion (e.g., due to CFCs) increases UV reaching the surface.

Human Impacts

• Air pollution (smoke, particulate matter, NOx, SO2) causes smog, health problems and acid rain.
• Increased greenhouse gases from burning fossil fuels lead to global warming and climate change.
• Protection measures include reducing emissions, planting trees, and regulating pollutant chemicals.

Summary

The atmosphere is essential for life and affects weather, climate and protection from Sun’s harmful radiation. Understanding its layers, composition and human impacts helps us protect the environment.

Definition: The lithosphere is the solid, outermost layer of the Earth — commonly called the land. It includes rocks, mountains, plateaus, plains, soils, and the crust that floats on the hotter, more plastic asthenosphere beneath.

Composition and Structure:

• Rocks: Made of different minerals and grouped into three major types: igneous (formed from cooled magma; e.g., basalt, granite), sedimentary (formed by deposition and cementation; e.g., sandstone, limestone), and metamorphic (altered by heat and pressure; e.g., marble, schist).
• Soil: The uppermost weathered layer that supports plant life. A typical soil profile has horizons: O (organic), A (topsoil), B (subsoil), C (parent material).
• Crust and Plates: The lithosphere includes continental and oceanic crust broken into tectonic plates whose movement shapes major landforms.

Major Landforms: Mountains, plateaus, plains, hills, valleys, deserts, coastal plains. These differ in elevation, slope, and origin (tectonic, volcanic, erosional, depositional).

Processes that Shape the Lithosphere:

• Plate tectonics: Colliding plates form mountains (e.g., Himalaya), diverging plates form rift valleys, subduction leads to volcanic arcs.
• Weathering: Breakdown of rocks by physical (freeze-thaw, temperature change), chemical (acid rain, oxidation), and biological (roots) processes.
• Erosion and transportation: Moving agents (water, wind, ice) remove and carry rock particles.
• Deposition: Sediments settle to form plains, deltas, and dunes.
• Mass movements: Landslides, rockfalls and soil creep change slope shapes quickly or slowly.

Importance of the Lithosphere:

• Provides land for human settlement, agriculture and infrastructure.
• Source of minerals, rocks, and fuels (coal, petroleum in sedimentary basins).
• Determines soil types and fertility which control vegetation and crop patterns.
• Influences climate locally by elevation and surface characteristics.

Human Interaction and Environmental Issues: Agriculture (soil use and erosion), mining (land degradation), deforestation (soil loss, landslides), urbanization (soil sealing), and desertification. Sustainable practices include soil conservation (contour ploughing, terracing), afforestation, controlled mining, and land-use planning.

Summary: The lithosphere is the Earth's solid land layer formed and continually reshaped by internal forces (tectonics, volcanism) and external agents (weathering, erosion, deposition). Understanding its features and processes helps manage natural resources and reduce hazards.

What is the hydrosphere? The hydrosphere is the part of Earth that contains water in all its forms — liquid, solid (ice) and gas (vapour). It includes oceans, seas, rivers, lakes, groundwater, glaciers, soil moisture and atmospheric water vapour.

Main components

• Oceans and seas: The largest reservoir of Earth’s water; salty and cover most of the planet.
• Rivers and lakes: Surface freshwater used for drinking, irrigation and transport.
• Groundwater: Water stored under the ground in aquifers; tapped by wells and tube wells.
• Glaciers and ice caps: Frozen freshwater, especially in polar regions and high mountains.
• Atmospheric water: Water vapour and clouds that move moisture around the globe.

Distribution of Earth’s water (approx.)

• Oceans (saline): ~97%
• Freshwater: ~3% (of which about 69% is locked in glaciers and ice caps, ~30% is groundwater, and only ~1% is surface water like rivers and lakes)

The water (hydrological) cycle — main processes

• Evaporation: Water from oceans, lakes and soil turns into vapour due to heat.
• Transpiration: Plants release water vapour from leaves.
• Condensation: Vapour cools and forms clouds.
• Precipitation: Water falls as rain, snow or hail.
• Infiltration and Percolation: Some water seeps into the ground to recharge groundwater.
• Runoff: Water flows over land into rivers and back to oceans.

Why hydrosphere is important

• Supports life: All organisms need water to live and grow.
• Regulates climate: Oceans store and transport heat, moderating weather and climate.
• Economic uses: Agriculture, industry, transport, energy (hydropower) and fishing.
• Shapes the landscape: Rivers carve valleys, waves form coasts, glaciers shape mountains.

Threats to the hydrosphere

• Pollution: Industrial effluents, sewage, plastic waste and oil spills contaminate water.
• Overuse and depletion: Excessive groundwater pumping and unsustainable irrigation.
• Climate change: Melting glaciers, sea-level rise and changing rainfall patterns.
• Destruction of wetlands and deforestation: Reduces natural water storage and filtration.

Conservation and management

• Rainwater harvesting, recharging groundwater and water-saving irrigation (drip irrigation).
• Proper treatment of industrial and domestic sewage; reducing plastic use.
• Integrated water resource management: balancing use among agriculture, industry and households.

What is the Biosphere?

The biosphere is the zone on Earth where life exists. It includes parts of the atmosphere (lower air), the lithosphere (uppermost crust), and the hydrosphere (water). All ecosystems together form the biosphere.

What is an Ecosystem?

An ecosystem is a functional unit made up of living organisms (plants, animals, microbes) and their physical environment interacting as a system. It can be as small as a puddle or as large as a forest.

Components of an Ecosystem

• Biotic (living): Producers (plants, algae), Consumers (herbivores, carnivores, omnivores), Decomposers (bacteria, fungi).
• Abiotic (non-living): Sunlight, air, water, soil, temperature, minerals.

How ecosystems work

• Energy flow: Sunlight → Producers (make food by photosynthesis) → Consumers → Decomposers. Energy flows in one direction and decreases at each trophic level.
• Nutrient cycling: Elements like carbon, nitrogen and water cycle between living organisms and the environment (biogeochemical cycles).

Types of Ecosystems

• Natural: Forests, grasslands, deserts, freshwater (ponds, rivers), marine (oceans, coral reefs), wetlands, mangroves.
• Artificial (man-made): Croplands, gardens, urban parks, reservoirs.

Ecological Concepts Useful for Class 7

• Producers: Make organic food from sunlight (e.g., green plants, algae).
• Consumers: Herbivores eat producers, carnivores eat other animals, omnivores eat both.
• Decomposers: Break down dead matter and return nutrients to soil.
• Food chain & food web: A food chain shows a single path of energy flow (e.g., grass → grasshopper → frog → snake). A food web shows multiple connected chains in an ecosystem.
• Pyramid of numbers/biomass/energy: Visual ways to show how number, mass and energy change across trophic levels.

Human impacts and conservation

Humans affect ecosystems by deforestation, pollution, overfishing, urbanization and introducing invasive species. Conservation measures include protecting habitats (wildlife sanctuaries, national parks), sustainable farming, afforestation, and pollution control.

Why this matters

Healthy ecosystems provide services: clean air and water, food, climate regulation, pollination of crops, soil formation and cultural values. Protecting the biosphere is essential for human well‑being.

Food Chain

A food chain is a simple, linear sequence that shows how energy and matter flow from one organism to another. It always begins with a producer (an organism that makes its own food) and ends with a top consumer or decomposer.

• Producers: Green plants and algae that make food by photosynthesis.
• Consumers: Organisms that eat other organisms. They are classified as herbivores (primary consumers), carnivores (secondary/tertiary consumers) and omnivores.
• Decomposers: Bacteria, fungi and some animals that break down dead matter and return nutrients to the soil.

Types of Food Chains

• Grazing (detritus) food chain: Starts with green plants eaten by herbivores and continues to carnivores.
• Detritus food chain: Starts with dead organic matter (leaves, dead bodies) eaten by detritivores and then by their predators; decomposers recycle nutrients.

Food Web

A food web is a network of many interconnected food chains in an ecosystem. It shows that most organisms feed on, and are eaten by, more than one species. Food webs give a more realistic picture of energy flow and species relationships than single food chains.

Energy Flow and Trophic Levels

Energy enters ecosystems through producers (solar energy → chemical energy) and flows up through trophic levels: producers → primary consumers → secondary consumers → tertiary consumers. Energy flow is unidirectional — it cannot be recycled. At each transfer, a large part of energy is lost to the environment as heat due to respiration, movement and metabolic processes.

• Trophic level: The position an organism occupies in a food chain (level 1 = producers, level 2 = primary consumers, etc.).
• 10% rule (approx.): On average only about 10% of the energy at one trophic level is available to the next level; roughly 90% is lost.

Pyramids

Pyramids are graphical representations of trophic structure:

• Pyramid of Numbers: Shows number of organisms at each trophic level.
• Pyramid of Biomass: Shows total biomass (mass of living material) at each level (e.g., kg/m²).
• Pyramid of Energy: Shows energy content at each level (kJ/m²/year) — always upright because energy decreases up the chain.

Importance

Understanding food chains, food webs and energy flow helps explain ecosystem stability, how pollutants or overfishing affect higher levels, and why there are fewer large predators than plants.

Short Numerical Example

If plants (producers) capture 10,000 kJ of energy in a year, then using the ~10% rule:

• Energy at primary consumers ≈ 10% of 10,000 = 1,000 kJ
• Secondary consumers ≈ 10% of 1,000 = 100 kJ
• Tertiary consumers ≈ 10% of 100 = 10 kJ

This shows why energy and biomass decrease at higher trophic levels.

What are natural resources?
Natural resources are materials and components that occur in nature and are useful to humans. They include things we use directly (water, soil, wood) and sources of energy (sun, wind, coal).

Why are they important?
Natural resources provide food, shelter, fuel, raw materials for industries and help maintain ecosystems. They support our daily life and economic activities.

Classification

• By origin: Biotic (derived from living organisms, e.g., forests, animals) and Abiotic (non-living, e.g., minerals, water, air).
• By renewability: Renewable (can be replenished naturally in a short time, e.g., sunlight, wind, forests if managed) and Non-renewable (finite and take millions of years to form, e.g., coal, petroleum, minerals).

Characteristics
Natural resources are unevenly distributed across the Earth. Some are abundant, others are scarce. Human use and mismanagement can lead to depletion and environmental damage.

Causes of depletion and problems
Overpopulation, excessive consumption, unsustainable farming and mining, deforestation, pollution and waste lead to resource degradation: reduced soil fertility, groundwater depletion, loss of biodiversity and air/water pollution.

Conservation and sustainable use
Conservation means using resources carefully so future generations can also use them. Key methods include: rainwater harvesting, watershed management, afforestation and reforestation, soil conservation (contour ploughing, terracing), sustainable agriculture, controlled mining, using renewable energy (solar, wind, biomass), reduce-reuse-recycle, protected areas and community-based resource management.

Role of individuals and society
Every person can help: save water, plant trees, reduce waste, recycle, use energy-efficient appliances and support policies for sustainable resource use.

Human-Environment Interaction describes the continuous relationship between people and their surroundings — how humans depend on, modify and adapt to the natural environment. This interaction shapes landscapes, climate impact, resource availability and the well-being of societies.

Key aspects:

• Dependence: People rely on the environment for food, water, shelter, fuel and raw materials (for example, crops from soil, fish from rivers).
• Modification: To meet needs, humans change environments — clearing forests for agriculture, building dams, constructing cities, mining minerals.
• Adaptation: Societies adjust to environmental conditions — e.g., people build houses on stilts in flood-prone areas, terrace farming on slopes, or adopt drought-resistant crops.
• Feedback and consequences: Changes often create feedbacks. Some are positive (improved living standards), others are negative (soil erosion, pollution, flooding). These feedbacks require further adaptation or correction.

Types of impacts:

• Physical changes: Deforestation, land-use change, river diversion, urban expansion.
• Biological/ecological effects: Loss of biodiversity, habitat fragmentation, soil degradation.
• Chemical/pollution effects: Air and water pollution, chemical contamination from industries and agriculture.

Sustainability and balance: Human-environment interaction aims to maintain a balance so natural resources meet present needs without compromising future generations. Sustainable practices include rainwater harvesting, afforestation, crop rotation, controlled grazing, renewable energy use and pollution control.

Role of technology and population: Technology influences how much pressure humans place on the environment (can reduce or increase impact). Population size and consumption patterns determine overall resource demand; larger populations or higher per-capita consumption usually mean greater environmental impact unless offset by cleaner technology and conservation.

Classroom connection: Understanding these interactions helps explain why communities choose certain livelihoods, how local actions can cause regional or global effects (e.g., greenhouse gas emissions) and why sustainable choices matter.

What are Environmental Problems? Environmental problems are disturbances to the natural environment caused by human activities or natural events that reduce the quality, functioning or availability of natural resources (air, water, soil, forests, biodiversity). They affect people’s health, livelihoods and the survival of plants and animals.

Main types of environmental problems

1. Air pollution: Contamination of air by smoke, dust, harmful gases and particulate matter from industries, vehicles, burning of fossil fuels and stubble burning. It causes respiratory diseases, smog and acid rain.

2. Water pollution: Contamination of rivers, lakes and groundwater by industrial effluents, sewage, agricultural runoff (pesticides, fertilizers) and plastic waste. It affects drinking water, aquatic life and agriculture.

3. Soil degradation and land pollution: Loss of soil fertility due to overuse of chemical fertilizers, erosion, deforestation, mining and dumping of solid waste and plastics.

4. Deforestation: Large-scale cutting of trees for agriculture, timber, settlements and roads. This reduces biodiversity, increases soil erosion and alters rainfall patterns.

5. Waste management problems: Inadequate collection and disposal of solid and hazardous waste leads to open dumping, illegal landfills, and microplastic pollution.

6. Loss of biodiversity: Extinction or decline of species due to habitat destruction, pollution, over-exploitation and invasive species.

7. Climate change and global warming: Increase in average global temperatures caused mainly by greenhouse gas emissions (CO2, methane) leading to changing weather patterns, more extreme events (floods, droughts) and sea level rise.

8. Ozone depletion and acidification: Release of certain chemicals (e.g., CFCs) reduces the ozone layer; air pollutants can cause acid rain that damages soil, forests and buildings.

Causes: Rapid population growth and urbanisation, industrialisation, unsustainable agriculture, deforestation, overuse of fossil fuels, improper waste disposal, and lack of environmental awareness and regulations.

Effects: Health problems (asthma, waterborne diseases), reduced crop yields, extinction of species, altered climate and weather patterns, shortage of clean water, soil infertility, economic losses and deterioration of cultural monuments.

Solutions and ways to reduce problems (practical actions):

• Reduce-Reuse-Recycle (3Rs): segregate waste, recycle paper/plastics and compost organic waste.
• Afforestation and reforestation: planting trees and protecting forests.
• Use cleaner energy: solar, wind and biogas; reduce dependence on coal and petrol/diesel.
• Water conservation: rainwater harvesting, watershed management, efficient irrigation (drip/sprinkler).
• Pollution control technologies and laws: effluent treatment plants, emission norms, fines for illegal dumping.
• Sustainable agriculture: crop rotation, organic farming, reduced chemical use.
• Public awareness and community action: environmental education, clean-up drives and conservation programmes.

Role of individuals and government: Individuals can reduce waste, save water and energy, use public transport and plant trees. Governments make policies (environmental laws, protected areas, pollution control boards), run national missions (e.g., Swachh Bharat, air and river cleaning programmes) and monitor environment health.

Importance for Class 7 students: Understanding environmental problems helps students become responsible citizens who can make daily choices that protect the environment — from reducing plastic use to saving water and spreading awareness.

What is Conservation and Why It Matters?

Conservation means protecting and wisely using natural resources so that they remain available for present and future generations. Sustainable practices are ways of using resources that meet current needs without harming the environment or reducing the ability of future generations to meet their needs.

Main Goals

• Protect biodiversity (plants, animals and their habitats).
• Prevent soil, water and air pollution and reduce resource depletion.
• Ensure continued availability of resources like water, forests and fertile soil.

Causes of Resource Degradation

• Deforestation for agriculture, industry and urban growth.
• Over-extraction of groundwater and surface water.
• Unsustainable farming (excessive chemical use, monocultures) causing soil erosion and loss of fertility.
• Pollution from industries, vehicles and improper waste disposal.

Basic Principles of Conservation

• Reduce: Use less by avoiding waste.
• Reuse: Use items more than once or repurpose them.
• Recycle: Convert waste into reusable material.
• Protect habitats: Maintain forests, wetlands and grasslands.
• Use resources efficiently: Use water, energy and land in ways that give more benefit with less input.

Practical Sustainable Practices

• Water conservation: rainwater harvesting, drip irrigation, fixing leaks, storing roof runoff.
• Soil conservation: contour ploughing, terrace farming, mulching, planting cover crops and trees (afforestation/ agroforestry).
• Forest and wildlife protection: creating protected areas, community forest management and avoiding illegal logging.
• Sustainable agriculture: organic farming, crop rotation, integrated pest management and mixed cropping.
• Waste management: segregation at source, composting biodegradable waste, recycling plastics and metals, reducing single-use items.
• Energy conservation and renewable energy: use of solar panels, efficient stoves, energy efficient appliances.

Role of Communities, Schools and Government

• Community actions: local water harvesting, plantation drives, community monitoring of forests and wildlife.
• Schools: environmental education, eco-clubs, tree plantation, waste segregation and recycling projects.
• Government actions: laws (Wildlife Protection Act, Forest Conservation Act), protected areas (national parks, wildlife sanctuaries), schemes for watershed management and afforestation.

How Students Can Help

• Practice Reduce, Reuse, Recycle at home and school.
• Plant and care for trees, join eco-club activities.
• Save water and electricity, avoid wasting food, and spread awareness.

Conclusion: Conservation and sustainable practices combine small everyday actions and large policy measures. Together they protect the environment, support livelihoods and make sure natural resources last for the future.

What is biodiversity? Biodiversity means the variety of life on Earth — the different plants, animals, microorganisms, the genes they contain, and the ecosystems they form. It is usually described at three levels: genetic diversity (variations within a species), species diversity (different species in an area), and ecosystem diversity (different habitats like forests, wetlands, grasslands).

Why is biodiversity important?

• Ecological balance: Species interact (food chains, pollination, nutrient cycles) to keep ecosystems healthy.
• Economic benefits: Many medicines, food, fuel, fibres and raw materials come from wild species.
• Cultural and recreational value: Many communities depend on local biodiversity for their culture, festivals and livelihoods; nature tourism also depends on it.
• Scientific value: Wild species help us learn about biology and develop new technologies and medicines.

Major threats to biodiversity

• Habitat loss and fragmentation: forests cleared for farming, cities and roads.
• Over-exploitation: excessive hunting, fishing or collection (e.g., overfishing).
• Pollution: water, air and soil pollution harm species and habitats.
• Invasive species: non-native species can outcompete and displace local species.
• Climate change: alters habitats and life cycles, causing range shifts and extinctions.

Wildlife conservation — how we protect biodiversity

Conservation methods fall into two main types:

• In-situ conservation (protecting species in their natural habitats): national parks, wildlife sanctuaries, biosphere reserves, conservation reserves and community reserves. Examples: Kaziranga National Park (one-horned rhinoceros), Gir National Park (Asiatic lion), Sundarbans (mangroves and Royal Bengal tiger).
• Ex-situ conservation (protecting species outside natural habitats): zoos, botanical gardens, captive breeding programs, seed banks and gene banks. Example: captive breeding of the Indian rhinoceros and release programs.

Laws, programmes and community role

• Important laws and programmes in India: Wildlife Protection Act (1972), Project Tiger (1973), Project Elephant, Biodiversity Act (2002), and creation of protected areas.
• Community participation: Many conservation efforts succeed when local communities are involved in sustainable use, eco-tourism, patrolling and habitat restoration.

Simple conservation actions students can take

• Plant native trees and protect local habitats.
• Reduce, reuse and recycle to lower pollution and resource use.
• Avoid products made from endangered species and spread awareness.
• Participate in local clean-up, tree-planting or citizen science projects (bird counts, surveys).

Summary: Biodiversity is essential for healthy ecosystems and human well-being. Protecting wildlife requires legal protection, habitat conservation, scientific management and active participation of people.

The environment is shaped by actions at three interlinked levels: individuals, the community (local groups and institutions) and the government. All three have distinct but complementary roles in conserving natural resources, reducing pollution and ensuring sustainable development.

Role of Individuals

• Daily habits: conserve water and energy (turn off taps, use LED bulbs), reduce use of plastics (carry cloth bags), choose public transport or cycle.
• Waste management at home: follow the rule “Reduce, Reuse, Recycle” — segregate biodegradable and non-biodegradable waste, compost organic waste, reduce food waste.
• Conservation actions: plant and care for trees, avoid burning leaves/garbage, use water-saving devices, repair and reuse items before discarding.
• Awareness and behaviour: learn and follow local rules, support sustainable products, educate children and neighbours about environmental practices.

Role of the Community

• Collective action: organise clean-up drives, tree plantations, community compost pits, and local recycling centres.
• Local systems and norms: set up neighbourhood waste segregation, community rainwater-harvesting systems, or shared public-transport initiatives.
• Support vulnerable workers: create cooperatives for waste pickers, provide training and fair prices for recycled materials.
• Awareness and advocacy: hold awareness camps, school programmes and local petitions to influence policies or enforcement.

Role of Government

• Policy and regulation: make and enforce environmental laws (air/water quality standards, waste-management rules, bans on single-use plastics).
• Infrastructure and services: provide reliable public transport, sewage treatment, landfills, recycling facilities and safe drinking water.
• Incentives and disincentives: subsidies for renewable energy, penalties for polluters, grants for conservation projects.
• Planning and long-term measures: environmental impact assessments, urban planning, national programmes for clean air, afforestation and climate adaptation.

Why all three are needed

Individuals reduce daily pressure on the environment, communities scale and sustain local solutions, and governments create the rules and infrastructure that make sustainable choices possible and fair. Effective environmental protection depends on coordination among all three levels.

Tips for students (practical steps)

• Start a small compost at home or join a community compost pit.
• Organise a school or locality clean-up and measure the waste collected.
• Write to local representatives if public services (waste collection, water supply) are poor.