(i) Certain plants, e.g. Pinus, Juniparus, Quercus, Pyrus and Vitis can metabolise nitrogen oxide (NO) and therefore, their plantation could help in reducing photochemical smog.
(ii) Liquefied CO₂ with a suitable detergent is used for dry cleaning and H₂O₂ is used for the better results and makes use of lesser amount of water.
(iii) Soaps are 100% biodegradable so they should be used in place of detergents. Now-a-days biodegradable detergents are available. Therefore, they should be used in place of non-biodegradable hard detergents.
(iv) CNG should be used as it causes much less pollution. Moreover, electrical vehicles should be used to reduce the consumption of petrol and diesel

Yes, it can be controlled by the following methods.
(i) Insecticides, pesticides which are used for the protection of our crops cause soil pollution. Herbicides (weed killers) also cause soil pollution. Therefore, there is a need for their judicious use.
(ii) After the World War-II, DDT was put to use in agriculture to control the damages caused by insects, due to adverse effects, its use has been banned in India. Pesticides such as aldrin and dieldrin are organic toxins. These are water insoluble and physiological disorders in animals. Now a days organophosphates and carbamates are also used as pesticides. These are more biodegradable but these chemicals are severe nerve toxins and hence, more harmful to human
Therefore, chemicals like fertilisers, detergents pesticides polymers, should be used only when necessary
(iii) Biodegradable domestic waste should be deposited in land fills.
(iv  ) Non- biodegradable waste should be recycled.
(v) use of polythene should be avoided.
(vi) Household waste, biological waste and chemical waste is often incinerated. Incineration greatly reduces the waste volume.

Yes, polluted water is the water whose quality has been degraded by the addition of substance such as chemical effluents, metal residues, sewage, oil, fertilisers, detergents, etc.
It can be controlled by the following methods.
(i) Industrial waste discharge from paper, fertilisers, should not be allowed to get mixed in water bodies such as river, lakes, etc.
(ii) Non-biodegradable detergents should be used for cleaning of clothes
(iii) The ph of water should be checked.
(iv) Excessive use of fertilisers should be prevented.
(v) oils spills should be avoided as much as possible
(vi) Domestic waste water should be properly discharged and treated.
(vii) Avoid the use of DDT, malathion at home.
(viii) Waste water should be treated in sewage treatment plant.

(a) Eutrophication: When the growth of algaes increases in the surface of water, dissolved oxygen in water is reduced. This phenomenon is known as eutrophication. (Due to this growth of fish gets inhibited).
(b) Pneumoconiosis: It is a disease which irritates lungs. It causes scarring or fibrosis
of the lung.

It is the phenomenon in which earth's atmosphere traps the heat from the sun and prevents it from escaping in outer space. Gases such as CO₂, methane, ozone, CFCs are believed to be responsible for this effect.
Heat from the sun after being absorbed by the earth is absorbed by CO₂ and then radiated back to the earth. Thus making the environment of the earth warm.

This is a type of smog formed in warm, dry and sunny climate. They are formed when sunlight is absorbed by SO₂, oxides of nitrogen and hydrocarbons. They act as oxidising agents.
Effects of photochemical smog.
(i) They produce irritation in the eyes and also in respiratory system.
(ii) They can damage many materials such as metals, stones, building materials etc.
(iii) NO₂ present gives a brown colour to the photochemical smog which reduces visibility.
(iv) It is harmful to fabrics, crops and ornamental plants.
Control of photochemical smog
(i) By using catalytic converters in automobiles.
(ii) By spraying certain compounds into atmosphere which generate free radicals that can easily combine with the free radicals that initiate the reaction forming toxic compounds of photochemical smog.
(iii) Certain plants such as pinus, juniparus, Pyrus could be helpful in this matter.

Acid rain is the rain water mixed with small amount of sulphuric acid, nitric acid along with hydrochloric acid which are formed from the oxides of sulphur and nitrogen present in air as pollutants. It has a pH of 4-5.
Harmful effects of Acid Rain
(i) It is toxic to vegetation and aquatic life.
(ii) It damages buildings and statues. Taj Mahal has been damaged by acid rain.
(iii) Acid rain corrodes water conducting pipes resulting in the leaching of heavy metals such as iron, lead, etc., to the drinking water.

Carbon monoxide is poisonous because it combines with haemoglobin of R.B.C. to form carboxyhaemoglobin as.
CO + Haemoglobin ⇌ Carboxyhaemoglobin
It inhibits the transport of oxygen to different parts of the body. Thus the body becomes oxygen-starved.

(i) Sonu became ill because of photochemical smog which caused iritation in his eyes and throat
(ii) Smog is formed when sunlight is absorbed by O₃, oxides of nitrogen and hydrocarbons.
(iii) Formation of smog can be prevented by controlling the emission of oxides of nitrogen and sulphur.
(iv) Nilesh is helpful, intelligent and curious.

As coke burns in a closed room, oxygen is used up and amount of oxygen in the room decreases. In the presence of carbon monoxide which is very poisonous because it combines with haemoglobin to form carboxy haemoglobin. This reaction takes place much more easily than reaction with oxygen to form oxyhaemoglobin. Thus supply of oxygen to body parts is hindered and this could be fatal.

As we go up the earth's surface, from 0-11 km (called troposphere), temperature decreases and from 11-50 km (called stratosphere). temperature increases. From 50-85 km (called mesosphere), temperature again decreases and family from 85-100 km (called thermosphere), temperature again increases.