Environmental Pollution

Environmental pollution is the release of substances and energy from the waste products of human activities. The key idea is that pollution is not just about adding something unwanted — it is about adding it in quantities and forms that overwhelm nature's ability to handle it.

Pollution is classified based on the medium through which the pollutants are transported and diffused. This gives us four main types: air pollution, water pollution, land pollution, and noise pollution.

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Water Pollution

Water from rivers, canals, and lakes is never completely pure. It naturally contains small amounts of suspended particles and organic or inorganic substances. The problem begins when the concentration of these substances rises so high that the water becomes unfit for use. At that point, the water's natural self-purifying capacity breaks down — it can no longer clean itself fast enough.

Sources of water pollution are both natural and human-made. Natural sources include erosion, landslides, and the decay of plants and animals. But the real concern is human activities — specifically industrial, agricultural, and cultural activities. Among these, industry is the most significant contributor.

Industries produce a long list of undesirable outputs: industrial wastes, polluted wastewater, poisonous gases, chemical residuals, heavy metals, dust, and smoke. Most of this waste is dumped directly into running water or lakes. The poisonous elements then reach reservoirs and rivers, destroying the entire bio-system of those water bodies. The major water-polluting industries are leather, pulp and paper, textiles, and chemicals.

Agriculture adds its own load. Modern farming uses inorganic fertilisers, pesticides, and herbicides. These chemicals are washed by rain into rivers, lakes, and tanks. They also infiltrate the soil and reach groundwater. Fertilisers, in particular, increase the nitrate content of surface waters.

Cultural activities — pilgrimage, religious fairs, tourism — also contribute to water pollution. In India, almost all surface water sources are contaminated and unfit for human consumption.

Health impact: Water pollution causes water-borne diseases. The most common are diarrhoea, intestinal worms, and hepatitis. According to the World Health Organization, about one-fourth of all communicable diseases in India are water-borne.

The Ganga and Yamuna: River pollution is a problem across all rivers, but the Ganga — flowing through one of the most populous regions — has caused the greatest concern. The table below summarises the pollution sources for these two rivers.

To improve the condition of the Ganga, the National Mission for Clean Ganga was initiated, and the Namami Gange Programme was launched. Its objectives include:

• Developing sewerage treatment systems in towns
• Monitoring industrial effluents
• Developing the river front
• Afforestation along the banks to increase biodiversity
• Cleaning the river surface
• Developing 'Ganga Grams' in Uttarakhand, Uttar Pradesh, Bihar, Jharkhand, and West Bengal
• Creating public awareness to avoid adding pollutants into the river, even through rituals

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Air Pollution

Air pollution is the addition of contaminants — dust, fumes, gas, fog, odour, smoke, or vapour — to the air in substantial proportion and for a duration that may harm flora, fauna, and property.

The main cause is the increasing use of varieties of fuels as energy sources. Combustion of fossil fuels, mining, and industries are the primary sources. These processes release:

• Oxides of sulphur and nitrogen
• Hydrocarbons
• Carbon dioxide and carbon monoxide
• Lead and asbestos

Health impact: Air pollution causes diseases related to the respiratory, nervous, and circulatory systems.

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Land Pollution

Land pollution arises from improper human activities, especially the disposal of untreated industrial waste and the use of pesticides and fertilisers. The pollutants include human and animal excreta, viruses and bacteria, garbage and the vectors (carriers of disease) it attracts, pesticide and fertiliser residues, alkalinity, fluorides, and radioactive substances.

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Noise Pollution

Noise pollution is defined as a high level of noise above the tolerance level. Its sources include aircraft, automobiles, trains, industrial processing, and advertising media. It is hazardous in many metropolitan and big cities in India, especially near industrial areas, transportation arteries, and airports.

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Summary Table: Types and Sources of Pollution