(i) Catalytic converter:
1. Used in automobiles for reducing emission of harmful gases.
2. They have expensive metals like platinum, palladium and rhodium as catalysts.
3. As the exhaust passes through the catalytic converter, unburnt hydrocarbons are converted to CO₂ and water, carbon monoxide & nitric oxide are changed into CO₂ & nitrogen gas respectively.
4. Vehicles fitted with catalytic convertor must use unleaded petrol as lead will inactivate the catalyst.
(ii) Ecosan toilets
1. Ecological sanitation, commonly abbreviated as ecosan, is an approach to sanitation provision which aims to safely reuse excreta in agriculture.
2. It desires to close the loop' mainly for the nutrients and organic matter between sanitation and agriculture

(i) Less use of fossil fuels.
(ii) Planting more and more trees.
(iii) Recycling of the wastes to reduce their quantity and produce useful materials.
(iv) Less or no use of fertilizers and pesticides.
(v) Dispose off the solid wastes in landfills.

1. Improvement of the purifying performance of waste water treatment plants, installing tertiary treatment systems to reduce nutrient concentration.
2. Implementation of effective filter ecosystems to remove nitrogen and phosphorus present in the run-off water.
3. Reduction of phosphorus in detergents.
4. Rationalisation of agricultural techniques through proper planning of fertilization and use of slow release fertilizers.
5. Use of alternative practices in animal husbandry to limit the production of waste water.

1. Wastes generated at home include vegetable and fruit peels, tea leaves, egg shells, newspapers, plastic carry bags, domestic sewage, glass, cloth etc.
2. Wastes generated at school include waste papers, pencil shavings, pen refills, food wrappers, sewage etc.
3. Wastes generated during trips include disposable plates, cups, glasses, spoons, paper napkins etc. and wrappers of ready made food items. The generation of following wastes can be reduced.
4. Paper, paper cups, plastic bags, glass bottles, plastic spoons/plates, etc. The generation of following waste is difficult to reduce.
5. E.g. Pencil shavings, refills of pens, peels of fruits etc.