Chapters :



In this chapter you will be able to understand:

  • Concepts of pollution and how it is a degrading our environment
  • The various types of pollution and its sources
  • The ecological and health hazards of these pollution
  • The effective strategies to reduce pollution and its impact
  • The different waste generated from various sources and impact in environment 
  • The issue of waste management
  • Recycling and efficient techniques to manage waste
  • Various legislations and policies employed by the government to protect the environment


In the previous chapters we have seen how humankind is using and overexploiting the natural resources and systems in this planet. Continuous unchecked usage has resulted in severe altercations and damage to our surrounding ultimately threatening the survival of every kind of life forms on earth. The Mother Nature is giving beyond its replenish able capacity and this is frequently resulting in several natural and man-made calamities. 

Environmental degradation is the exhaustion of the world’s natural resources: land, air, water, soil, etc. Individuals are disposing of wastes that pollute the environment at rates exceeding the wastes’ rate of decomposition or dissipation and are overusing the renewable resources such as agricultural soils, forest trees, ocean fisheries, etc. at rates exceeding their natural abilities to renew themselves. Therefore, the environment’s capacity to withstand the negative impacts due to human activities has diminished and environmental degradation has become a threatening issue.

Environmental degradation has become a “common concern” for humankind over the past few decades. The distinctive nature of the present environmental problems is that they are caused more by anthropogenic than natural phenomena. Mindless consumerism and economic growth have started to demonstrate pernicious effects on Mother Nature. In spite of this, the pace and desire for economic development have never ceased. To most investors overexploitation of natural resources is more profitable in the short run, due to cheap means of disposing of wastes, avoiding the costs of waste treatment and the excluding of social losses in cost calculations. However, in the long run natural resources will be depleted and the losses will be irreversible. Due to the severity of environmental degradation all over the world, the World Bank and other environmental institutions have conducted studies to present a cost assessment of environmental degradation 


Environmental pollution is the unfavourable alteration of our surroundings, wholly or largely as a by-product of man’s actions, through direct or indirect effects of the changes in the energy pattern, radiation levels, and chemical and physical constitution and abundance of organisms. 

Environmental pollution is a global problem and is common to both developed as well as developing countries, which attracts the attention of human beings for its severe long-term consequences. The decline in environmental quality as a consequence of pollution is evidenced by loss of vegetation, biological diversity, excessive amounts of harmful chemicals in the ambient atmosphere and in food grains, and growing risks of environmental accidents and threats to life support systems. 

Pollution is viewed from different angles by different people but is commonly agreed to be the outcome of urban-industrial and technological revolution and rapacious and speedy exploitation of natural resources, increased rate of exchange of matter and energy, and ever-increasing industrial wastes, urban effluents, and consumer goods. 

Singh (1991) has defined pollution in a very simple manner, i.e., Disequilibrium condition from equilibrium condition in any system.” This definition may be applied to all types of pollution ranging from physical to economic, political, social, and religious. Over the past couple of decades, various sources of pollution were identified that altered the composition of water, air, and soil of the environment. 

The substances that cause pollution are known as pollutants. A pollutant can be any chemical (toxic metal, radionuclides, organophosphorus compounds, gases) or geochemical substance (dust, sediment), biological organism or product, or physical substance (heat, radiation, sound wave) that is released intentionally or inadvertently by man into the environment with actual or potential adverse, harmful, unpleasant, or inconvenient effects. 

From an ecological perspective pollutants can be classified as follows:

  • Degradable or non-persistent pollutants: These can be rapidly broken down by natural pro- cesses. Eg: domestic sewage, discarded vegetables, etc.
    1. Slowly degradable or persistent pollutants: Pollutants that remain in the environment for many years in an unchanged condition and take decades or longer to degrade. Eg: DDT and most plastics.
  • Non-degradable pollutants: These cannot be degraded by natural processes. Once they are released into the environment they are difficult to eradicate and continue to accumulate. Eg: Toxic Elements Like Lead Or Mercury.

Such undesirable effects may be direct (affecting man) or indirect, being mediated via resource organisms or climate change. Depending on the nature of pollutants and also subsequent pollution of environmental components, the pollution may be categorized as follows:

  • Air Pollution
  • Water Pollution
  • Soil/Land Pollution
  • Noise Pollution
  • Radioactive Pollution
  • Thermal Pollution
  • Marine Pollution

Hence the let us study the various pollution its sources, impact and reduction strategies in the following section. 


 The origin of air pollution on the earth can be traced from the times when man started using firewood as a means of cooking and heating. Hippocrates has mentioned air pollution in 400 BC. With the discovery and increasing use of coal, air pollution became more pronounced especially in urban areas. It was recognized as a problem 700 years ago in London in the form of smoke pollution. During the industrial revolution due to the use of coal in industries air pollution became a major problem in London in the 19th century.  The earliest recorded major disaster was the ‘London Smog’ that occurred in 1952 that resulted in more than 4000 deaths due to the accumulation of air pollutants over the city for five days. Air pollution began to increase in the beginning of the twentieth century with the development of the transportation systems and large-scale use of petrol and diesel. The severe air quality problems due to the formation of photochemical smog from the combustion residues of diesel and petrol engines were felt for the first time in Los Angeles. Pollution due to auto-exhaust remains a serious environmental issue in many developed and developing countries including India. Air pollution is now considered to be the world’s largest environmental health threat, accounting for 7 million deaths around the world every year. 


Air pollution occurs due to the presence of undesirable solid or gaseous particles in the air in quantities that are harmful to human health and the environment. 

Natural causes such as volcanoes, which release ash, dust, sulphur and other gases, or by forest fires that are occasionally naturally caused by lightning. However, unlike pollutants from human activity, naturally occurring pollutants tend to remain in the atmosphere for a short time and do not lead to permanent atmospheric change.

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