Geography · Ch 17 — Geographical Perspective on Selected Issues and Problems
Water Pollution
Water Pollution
Water pollution is the degradation of water quality to the point where it becomes unfit for use. No surface water — from rivers, canals, or lakes — is ever 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 beyond a threshold. At that point, the water's natural self-purifying capacity breaks down, and the water becomes polluted.
Though natural events like erosion, landslides, and the decay of plants and animals do release pollutants, the real concern is human activity. People pollute water through three main channels: industrial, agricultural, and cultural activities. Among these, industry is the most significant contributor.
Types and Sources of Water Pollution
The textbook provides a clear classification of pollution types and their sources. For water pollution specifically, the pollutants include:
- Odour, dissolved and suspended solids
- Ammonia and urea, nitrates and nitrites
- Chloride, fluoride, carbonates
- Oil and grease
- Insecticide and pesticide residues
- Tannin and coliform MPN (bacterial count)
- Sulphates and sulphides
- Heavy metals such as lead, arsenic, mercury, and manganese
- Radioactive substances
These pollutants come from four main sources:
- Sewage disposal
- Urban run-off
- Toxic effluents from industries
- Run-off over cultivated lands and from nuclear power plants
Industrial Pollution
Industries produce a wide range of undesirable by-products: industrial wastes, polluted wastewater, poisonous gases, chemical residuals, heavy metals, dust, and smoke. Most of this waste is disposed of directly into running water or lakes. As a result, poisonous elements reach reservoirs, rivers, and other water bodies, destroying the entire bio-system of those waters. The major water-polluting industries are leather, pulp and paper, textiles, and chemicals.
Pollution of the Ganga and Yamuna
The textbook gives specific examples from India's most polluted rivers.
Ganga — polluted stretches are found downstream of Kanpur, downstream of Varanasi, and at the Farrakka Barrage. The main sources of pollution are:
- Industrial pollution from towns like Kanpur
- Domestic waste from urban centres such as Kanpur, Prayagraj, Varanasi, Patna, and Kolkata
- Dumping of carcasses into the river
Yamuna — polluted stretches run from Delhi to its confluence with the Chambal, and also near Mathura and Agra. The causes are:
- Extraction of water by Haryana and Uttar Pradesh for irrigation
- Agricultural run-off, which introduces high levels of micro-pollutants
- Domestic and industrial waste from Delhi flowing into the river
Agricultural and Cultural Pollution
Modern agriculture adds another layer of pollution. Inorganic fertilisers, pesticides, and herbicides are washed down into rivers, lakes, and tanks. These chemicals also infiltrate the soil and reach groundwater. Fertiliser use, in particular, increases 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 now contaminated and unfit for human consumption.
Health Impacts …
The photograph shows two men in a narrow wooden boat, one rowing and the other standing with a pole, cutting their way through a thick, pervasive layer of white-grey froth and foam that completely covers the surface of the Yamuna River. The foam is so dense and widespread that the water itself is barely visible — the boat appears to be moving through a solid-looking blanket of effluent. A dark, rocky bank is visible in the background, framing the scene.
This image is placed directly in the section on water pollution, immediately after the text explains that industrial, agricultural, and domestic wastes are the main causes of water quality degradation. The foam is not natural — it is a direct visual consequence of untreated industrial effluents and sewage being discharged into the river. Detergents, organic matter, and chemicals from factories (especially leather, textile, and chemical industries) create stable foam when the water is agitated, and the sheer volume of pollutants overwhelms the river's self-purifying capacity.
The caption's phrase "Cutting Through Effluent" is deliberately stark: the men are not rowing on water in any normal sense — they are forcing their boat through a layer of pollution so thick it behaves almost like a solid surface. The photograph makes concrete the textbook's statement that "most of the industrial wastes are disposed off in running water or lakes" and that "poisonous elements reach the reservoirs, rivers and other water bodies, which destroy the bio-system of these waters." …
| River and State | Polluted Stretches | Nature of Pollution | Main Polluters |
|---|---|---|---|
| Ganga (Uttar Pradesh) Bihar and West Bengal | (a) Downstream of Kanpur (b) Downstream of Varanasi (c) Farrakka Barrage | 1. Industrial pollution from towns like Kanpur 2. Domestic wastes from urban centres 3. Dumping of carcasses in the river | Cities of Kanpur, Prayagraj, Varanasi, Patna and Kolkata release domestic waste into the river |