NCERT Solutions Class 8th Science Chapter – 18 Pollution of Air And Water Question & Answer

• People dispose of garbage in the water.
• Many industries discharge their harmful chemicals directly into rivers and streams.
• Chemical fertilisers, pesticides and weedicides used in agricultural practices get dissolve in water and are washed away into water bodies from the fields.
• Untreated sewage is directly discharged into water from household activities.

• I will use public transport as far as possible.
• I will generate awareness among people to reduce air pollution.
• I will plant more and more trees because trees help to keep the environment clean and reduce air 1 pollution.
• I will not use vehicles for short distances.

• Chlorine tablets should be made available.
• Proper cleaning of the water tank from time to time.
• The water supply pipes should not come in contact with the sewage pipes.

• It increases corrosion of metals.
• It damages buildings and sculptural materials.
• It removes the basic nutrients such as calcium from the soil.
• It causes direct damage to plants and crops.
• It causes skin eruptions in human being.

• When we visit a park we find it full of fresh air and in a busy road we find it polluted due to fumes, smoke, dust and sound.
• An industrial area is more polluted as compared to residential area as industrial area gets polluted with chemical pollutants, toxic gases, etc.
• In early morning there is iess pollution but in afternoon it becomes a little more polluted than morning and in the evening it becomes extremely polluted.
• A town is more polluted than a village.

• Renewable sources of energy like solar energy, wind energy, etc. and avail maximum benefit from them.
• Less amount of non-renewable sources of energy, so that they last longer.

• Use of pesticides and fertilisers affect the quality of soil.
• Overgrazing done by animals damages the soil by eating the vegetation.

• By planting more trees and grass.
• By constructing dams and river embankments.

• Deforestation — due to increasing population and increasing industrialisation.
• Overgrazing — by large animal populations has destroyed vegetation and result in barren land.
• Poor Farming Method — ploughing, loosens the soil and destroys its natural resources.

• affects the monuments like Taj Mahal.
• spoils the growth of plants.
• causes irritation of eyes in human beings.

• Automobiles which bum petrol and diesel.
• Certain factories.
• Power plants.
• Mining of ores.

• Global warming is the gradual increase in average temperature of the earth’s atmosphere.
• This is caused due to the increased green house effect.
• The amount of carbon dioxide in the atmosphere is increasing due to the following factors
• Deforestation
• Increased human activities
• Industrialisation

Due to this global warming is taking place. It is expected that if it continues at this rate the glaciers will melt and the level of water in the oceans will rise.

• Use CNG or unleaded fuel for the vehicles.
• Say no to crackers during Diwali.
• Using alternative sources of energy instead of fossil fuels.
• By planting more trees.
• By not burning dried leaves, instead putting them in a compost pit.

• Smoke and dust from forest fires.
• Volcanic eruptions.
• Automobile exhausts.
• Factories and power plants.
• Burning of fire wood and dung cakes.

• Petroleum refineries release gaseous pollutants like sulphur dioxide and nitrogen dioxide.
• Power plants release sulphur dioxide due to burning of coal.
• Power plants give out tiny ask particles.
• Industrial processes also release particles in air.

• By filtering it, e.g., a candle type filter is used at home.
• By boiling the water to kill the germs. ,
• By adding chlorine tablets or bleaching powder.
• Ozone gas or iodine can be used.
• Ultraviolet rays are used in some water treatment systems.

• We avoid wastage of water.
• Reuse the water
• Recycle the water.
• Close the taps when water is hot required.
• Repair the taps to prevent leakage.

• greenhouse effect is reduced
• dust particles in the air are reduced.