Environmental pollution is defined as the contamination of air, water, or food in such a manner as to cause real or potential harm to human health or well-being, or to damage or harm nonhuman nature without justification. Pollution is an undesired change in the physical, chemical, or biological properties of soil, air, or water caused by the excessive accumulation of pollutants., i.e. substances which cause pollution.

Population explosion, expansion of industries, urbanization, use of insecticides, use of vehicles and nuclear energy has badly affected our environment (air, water and land) by releasing of various harmful chemicals and toxic materials including radioactive waste. This unfavorable alteration in the environment due to addition of harmful substances is called as pollution.


Pollutants are substances that pollute the environment. Sometimes the substances which are useful for one thing may be pollutant for another.

Pollutants are residues of things we make use and throne away. These are by products of man’s actions. They are the result of a technological society with a high standard of living. As the population grows, pollution and pollutants increase, resulting in less space available and greater per-personal needs.


(A) On the basis of their existence in nature, pollutants are of two types:

(i) Quantitative Pollutants: These are the substance which normally occur in nature but are also added in large quantities by man. They become pollutants only when the concentration reaches beyond a threshold value in the environment e.g. CO,CO2 and Nitrogen oxides.

(ii) Qualitative Pollutants: They do not occur in nature but are added by man e.g. DDT, insecticides and herbicides.

(B) On the basis of form in which the persist after release into the environment, pollutants are two types:

(i) Primary Pollutants: These persist in from in which they are added to the environment e.g DDT.

(ii) Secondary Pollutants: These are formed by reaction amongst the primary pollutants nitrogen oxide and hydrocarbons react in the presence of sun light to form two secondary pollutants such as PAN (peroxy acetyl nitrate) and ozone. econdary pollutants are more toxic than  primary pollutants. This phenomenon of increased toxicity due to reactions between pollutants is called synergism.

(C) From the ecosystem view point these pollutants can be classified into two basic types:

(i) Non degradable pollutants: The pollutants which cannot be degraded into less harmful substances by any natural method or degrade very slowly are called as non-degradable pollutants.

EXAMPLES: The waste materials and poisons like aluminium, plastic, mercury salt, DDT fungicides, other insecticides radioactive substance etc. These non-degradable pollutants not only accumulate but often biologically magnified as they move in biochemical cycles and along food chains. They also combine with other compounds in the environment to produce additional toxic.

(ii) Biodegradable pollutants: The pollutants which are degraded quickly into useful or less harmful substance by natural process like decomposition are called as biodegradable pollutants.

EXAMPLES: Domestic sewage, heat, cow, dung, etc. which can be rapidly decomposed by natural processes into less harmful substances


The pollution is of four major types :

1. Air pollution

2. Water pollution

3. Land pollution

4. Noise pollution



The atmosphere is a gaseous shell that surrounds the Earth from all sides, and  air is a mechanical mixture of several gases, primarily nitrogen (78.09%), oxygen (20.95%), and argon (0.93%) and carbon dioxide (0.03%). Air is very important for all types of life in the biosphere. Human life is not possible without air because one can live a few days without water or few minutes without air.

The air become polluted when its natural composition is disturbed either by natural or man-made sources or by both. Air pollution may be defined as The presence in the outdoor atmosphere of one or more contaminants such as dust, fumes, gas, mist, odour, smoke or vapour is quantises of characteristics and of duration such as to be injuries to human, plant or animal life and to propert or which unreasonably interferes with the comfortable enjoyment of life and property or Degradation of air quality and natural atmospheric condition constitute air pollution. The air pollutant may be gas or particulate matter.



There are two major sources of air pollution as follows:

(A) Natural Sources: These are the natural sources of air pollution that lies on the earth.The main natural sources are as follows:

1. Volcanic eruptions

2. Forest fire

3. Marshy Lands

4. Biological decay of organic and inorganic substances

5. From extra-terrestrial bodies

6. From green plants

(B) Anthropogenic Sources: These sources are manmade sources of air pollution. These are as follows:

1. Combustion

2. Production units of various industrial establishments

3. Agricultural Activities

4. Solvent Usage

5. Mining and purification of ores

6. Atomic projects


Following measures have been suggested to control air pollution.

1. The height of chimneys should be increased to the height possible level to reduce pollution at the ground level.

2. Trees should be planted on the roadside, riverbanks, parks, and open places as they keep the environment fresh.

3. Industries should be established away from the inhabitation region.

4. Some gases, which are move soluble in a particular liquid than air, for example, ammonia in water, can be separated by dissolving in it.

5. Particles larger than 50 mm are separated in gravity setting stacks. Five particles are separated by using cyclone collectors or electrostatic precipitators.

6. SO2 pollution can be controlled by extracting sulphur from the fuel before use.

7. In place of coal, petrol, the electrical battery operated vehicles should be used.

8. Nuclear explosion should be restricted.

9. Population growth, which is the main cause of pollution should be checked.



Water is the most important element in the biosphere because on one hand it is virtual for the maintenance of all forms of life and on the other hand it is virtual for the maintenance of all forms of life and on the other hand it helps in the movement, circulation and cycling of nutrients in the biosphere. It is found in various phases and in various storages such as :

1. In liquid phase: storage such as rivers, lakes, seas and oceans, soils, living organisms etc.

2. In solid phase: storages such as glaciers and ice sheets and ice caps like ice caps of Arctic region.

Like other natural substances has self-purifying capacity during recycling process but when the amount of foreign undesirable substances added by the man to the water exceeds the tolerance level and self-purifying capacity of water, it gets polluted.

Water pollution is defined as, ‘natural or induced change in the quality of water which renders it unsuitable or dangerous as regards food, human and animal health, industry, agricultural, fishing or leisure pursuits’.


Main sources of water pollution are:

1. Community waste waters: It includes discharge from houses, commercial and industrial establishments connected to public sewage system.

2. Industrial Wastes: The major source of water pollution is water discharged from industries into water bodies.

3. Agricultural Source (Fertilizers): Modern agricultural techniques require the use of millions of tons of artificial fertilizers to improve the fertility of land and obtain a better yield of crop.

4. Pesticides and Herbicides: Pesticides are widely used both in houses and in fields to eradicate the pests and protect the vegetation and stored grains.

5. Mineral Oils: Mineral oil discharged into water either by design or accident is extremely toxic is extremely toxic and adversely affects the living organisms.


Control of water pollution requires several remedial measures involving individuals, community, governments at national and international levels as follows:

1. The individuals must be educated enough to understand the nature of water pollution and its adverse effects on human health and wealth.

2. These must be mass awareness and correct perception at community level about various aspects of water pollution.

3. People must restrain themselves from throwing human and animal excreta and garbage’s into any water body.

4. Industrial units and Municipal Corporation must arrange for sewage treatment plants and treat polluted water be discharging effluents into lake and rivers.

5. Government should provide adequate funds to the municipal corporation for making water pollution control more effective.

6. Government must bring in force effective laws for water pollution control measures.

7. The individuals, communities, officials and the owners of mill must be tried in the courts of law and suitably penalized under strict laws, if they violate the provisions of pollution control.

8. Separate ponds and tanks to be used for cattle and animals.

9. Rivers and lakes should not be used for bathing or washing as it contaminates water.



Land pollution is a serious problem that impacts human, animals, and the earth. If no measures are taken to reduce pollution, permanent changes in the soil can occur.The adverse changes to the environment due to land pollution are subtle, but the problem is much bigger than it appears.

The basic definition of soil pollution is land destruction and pollution by direct and indirect human actions. Pollution leads to soil changes  such as soil erosion. Some  changes are irreversible, but some are not irreversible.


There are several known causes of land pollution. Of those, these are six factors that contribute more than others.

1. Deforestation and soil erosion

2. Agricultural chemicals

3. Industrialization

4. Mining

5. Landfills

6. Human sewage

7. Industrialization

8. Construction activities

9. Nuclear waste


There are several possible solutions to soil pollution, including nature maintenance. Conservation focuses on the conservation of natural resources such as soil and plants. Efforts to save resources can begin with the application of sustainable practices.

 For example, leave some  trees in the forest to wither and rot naturally. This not only leaves the necessary coverings for the soil and other vegetation, but also helps to provide the nutrients needed to keep the soil  fertile. Other solutions include:

1. Proper waste disposal that focuses on treating waste and disposing it in the safest manner possible.

2. Reusing materials to reduce the need for harvesting of resources. Products that cannot be reused may be recycled.

3. Reducing the usage of non-biodegradable materials, such as plastic shopping bags. Simply switch to a reusable fabric bag for groceries and reduce the need for non-biodegradable materials.

4. Organic gardening can reduce the usage of pesticides and insecticides .Non-gardeners can help by purchasing organic food.

5. Create dumping ground away from  residential areas.

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