Natural resources are materials and energy obtained from nature that are used by living organisms. Renewable resources: replenished naturally (sunlight, wind, water, forests if managed). Non-renewable resources: take millions of years to form and will be exhausted (fossil fuels, minerals). Conservation is essential because resources are finite and their misuse harms ecosystems. Sustainable development: meeting present needs without compromising the ability of future generations to meet their needs. The 3R principle — Reduce (use less), Reuse (use things again), Recycle (process waste into new products).

Forests provide timber, medicine, oxygen, regulate climate, prevent soil erosion, and are habitat for wildlife. Deforestation causes: loss of biodiversity, soil erosion, droughts, floods, climate change. Chipko Movement: 1970s, Uttarakhand — villagers hugged trees to prevent felling; led by Sundarlal Bahuguna. Stakeholders in forest management: local communities (depend on forests), forest departments, industries, wildlife conservationists — their interests often conflict. Wildlife sanctuaries and national parks protect species. Project Tiger, Project Elephant: government conservation programmes. Biodiversity hotspots: areas rich in endemic species but threatened by habitat loss (e.g., Western Ghats, Himalayas).

Water: essential for all life. Freshwater is only ~3% of total water on Earth. Water management: rainwater harvesting (collecting roof runoff into tanks/ponds), watershed management, check dams. Traditional systems: khadins (Rajasthan), johads, bandharas, surangams — community water conservation. Water pollution from industries and agriculture threatens freshwater bodies. Conservation of coal and petroleum: they are non-renewable; burning them releases CO₂ (greenhouse gas). Alternatives: solar energy, wind energy, biogas. Using public transport, cycling, improving fuel efficiency reduces petroleum use. Coal is used for electricity generation — thermal power plants are major polluters.

Renewable/alternative energy sources reduce dependence on fossil fuels and lower pollution. Solar energy: solar panels (photovoltaic cells) convert sunlight to electricity; solar cookers, solar water heaters. Wind energy: wind turbines convert wind kinetic energy to electricity; requires open, windy areas. Biogas: produced from anaerobic decomposition of cow dung, agricultural waste, sewage — mainly methane; used for cooking and lighting in rural India. Tidal energy: movement of ocean tides drives turbines. Hydroelectric power: kinetic energy of flowing water (dams). Geothermal energy: heat from inside Earth. Challenges: intermittency (solar/wind not always available), high initial cost, land use.