The general meaning of environment is ‘the surroundings about us’. There are three components of environment:
(i) Physical (abiotic) Component-Land, water, air and the related semi-components are included in it.
(ii) Biotic Component-Plants and animals are included in it. Man is an important part of it.
(iii) Energy Component-The sun is the main source of energy on the earth. So, it is also a part of our environment. Besides it, geothermal energy, tidal energy, wind energy etc. are also included in it.
Man is such a living being who gets affected by the environment as well as affects the environment the most. If we see the historical development order of geography, we find that in the beginning, the geographers had considered the environment stronger than man (Determinism). However, the scientific and technical development made man not only stronger but egoist also. Now he began to feel that Nature is under his control and he can give a fillip to development in the way he likes-the limits of development are infinite for man (Possibilism). Keeping this concept in view, man exploited Nature ruthlessly, the bad results of which began to come out immediately. And then, the geographers propounded the hypothesis of Neo-Determinism.
According to it, ‘Man is like that town traffic controller who can change the speed but not the direction.’ It means we shall have to boost up our development in such a way that the natural balance does not get disturbed. Otherwise, Nature will interfere and show us the way. In recent years the importance of conservation of Nature has been accepted universally. We have understood that if man has to save his existence, he will have to save Nature. In this context the concept of ‘sustainable development’ was also developed. Sustainable development means ‘to direct the present economic and social development in such a way that the Nature (environment) or resources could be kept safe for the coming generations.’
The meaning of ‘environmental pollution’ is- ‘loss in quality of environment on local level by human factors’ whereas that of ‘environmental degradation’ is- ‘loss in quality of environment on local, regional and world level by both natural and man-made factors.’
Under environmental pollution are included not only environmental issues but social, economic and ecological problems also. Prof Savindra Singh, while giving definition of environmental pollution in his book ‘Paryavaran Bhoogol’ writes-”The environment is polluted when there is this much change in the natural ecosystem by the desirable or undesirable work done by man that it is beyond the tolerance level of the ecosystem and as a result, there is far-reaching harmful impact on the human society because of loss in the quality of environment more than the desirable level”
Classification of Environmental Pollution
(A) Classification on the basis of the form of pollution
On this basis, pollution is divided into two major classes-physical pollution and social pollution.
Physical Pollution-When there is loss in the quality of physical components of the environment, we call it physical pollution. Land pollution, water pollution and air pollution are included in it.
Social Pollution-When there is decline in the quality of human society by various factors and processes, it is called social pollution, e.g., theft, dacoit, female exploitation and the like events. Economic pollution (poverty, unemployment), religious pollution (religion-impelled violence), racial or ethnic pollution (racial violence) and other social problems are included in it.
(B) Classification on the basis of the medium of pollution.
There are two major factors or sources of pollution-natural and man-made.
Natural Sources-The volcanic ash and dirt, problems developed after seismic events, flood, soil erosion and other natural disasters are included in it.
Man-made factors-Industrial, agricultural and population sources are included in it.
Industrial source-Harmful gases coming out from industries, e.g., nitrogen oxide, sulphur dioxide, carbon monoxide, hydrocarbons are included in it. The solid waste coming out from industries increase land pollution. In the same way, when industrial wastes without any purification are disposed off in rivers, lakes or oceans dire environmental problems come out several times. For example, when waste products with mercury from Minamata town near Japan coast were disposed off in high quantity in the Minamata Bay, the level of mercury increased in the fish found there. Several people died after consuming those fish. This fatal disease is famous even today as ‘Minamata disease’. Agricultural Source-The chemical fertilizers and insecticides used in agriculture create soil pollution as well as river pollution. Other Sources-Social pollution and other man-made factors are included in it.
(C) Classification on the basis of location of pollution
Pollution can be divided into two classes on the basis of location-point pollution and non-point pollution.
Point Pollution-Point pollution means ‘coming out of pollutants from a specified location’. For example-Disposing off drain pollutants into a river or lake, industrial wastes into rivers, lakes or oceans, and smoke from chimneys of factories into atmosphere. Point pollution is visible and anyone can understand it by seeing its form.
Non-point Pollution-Non-point pollution is not visible and clear. For example-Chemical fertilizers and insecticides are used for growth of crops. But the chemicals present in it are harmful to soil. When they reach rivers, lakes and oceans they also pollute them. In the same way, they also pollute underground water. When chemical fertilizers are used for a long time, the soil becomes infertile that results in gradual decrease in crop production which gives rise to economic pollution. Pollution occurring in the physical components of environment- land, water and air are mainly studied in geography.