Laws for industrial units should be strictly implemented so that polluted water is not disposed of directly into rivers and lakes. Water treatment plants should be installed in all industrial areas. We should individually follow a mantra Reduce, Reuse and Recycle. We can think of creative ideas like water used for washing can be reused for other tasks. Discharge of kitchen can be done in kitchen garden etc.

Water can be made safe for drinking by following ways:
(i) Water is filtered. Many filters available in the markets are used by people.
(ii) Some use boiling as a method for obtaining safe drinking water because boiling kills the germs present in the water.
(iii) Chlorination is a chemical method for purifying water.

Many industries discharge harmful chemicals into rivers and streams. For example, oil refineries, paper factories, textile, sugar mills and chemicals factories. The chemicals released include arsenic, lead and fluorine which lead to toxicity in plants and animals. Soil is also affected by impure water, causing changes in acidity, growth of worms etc.

If we drink polluted water, we may be affected from diseases such as cholera, typhoid, and jaundice as the polluted water contains many pathogens.

Water contains many disease carrying microbes and dissolved impurities. So,we need to filter water before drinking.

Untreated or inadequately treated sewage is a major source of ground water pollution. Sewage contains food wastes, detergents, micro-organisms, etc. which seep into the ground to pollute groundwater.

The disposal of garbage increases the pollution level. It gets so high that the aquatic life cannot survive as the water is not suitable for breathing.

False, CO is not a greenhouse gas. CO₂, CH₄, N₂O and CFCs are the principle greenhouse gases.

False, sun's rays do warm the earth's surface. This is infact necessary for existence of life on earth.

A large number of automobiles stop for a short period at red light throughout the day and release a large quantity of gases (due to burning of petrol and diesel) which leads to air pollution. Motor vehicles are the major cause of air pollution in big cities.

New fuel adopted was CNG (Compressed Natural Gas). It is a better fuel because
(i) it is cheaper than petrol.
(ii) it burns very efficiently.
(iii) it cannot be adulterated.

India's most famous tourist attraction 'Taj Mahal' is located at Agra. It has become a matter of concern in recent years due to increasing air pollution. Taj Mahal is made up of white marble. Experts have warned that air pollution is discolouring its white marble. The industries located around Agra produce pollutants like sulphur dioxide and nitrogen dioxide. These gases react with water vapours to form sulphuric acid and nitric acid respectively. These acids comes down along with rain as acid rain and corrodes the white marble of Taj Mahal. This phenomenon is also called as 'marble cancer'.

Global warming is an increase in the average temperature of the earth's surface. It occurs as a result of increased concentration of greenhouse gases in the atmosphere. The greenhouse gases such as CO₂, CH₄, etc are increasing due to human activities including vehicular emissions, burning of fossil fuels, etc. Global warming has become a major concern for governments worldwide. This is because even as little as 0.5⁰C Crise in temperature can have serious implications.

Clear, transparent water is not always fit for drinking as it may have many disease carrying microbes and dissolved impurities that are not visible to unaided eyes. So, transparent water also needs to be purified by various processes.

We can reduce air pollution by adopting the following steps:
(i) By saying no to crackers.
(ii) By using CNG and unleaded petrol.
(iii) By generating awareness about air pollution among friends and neighbours.
(iv) By using solar energy, hydropower instead of fossil fuels.
(v) By planting trees to reduce the level of carbon dioxide and air pollution.
(vi) Converting leaves into compost instead of burning them.