Geographical Perspective on Selected Issues — Environmental Pollution: Water, Air, Land & Noise

NCERT India: People and Economy — Unit V, Chapter 9 (Part 1)

What Is Environmental Pollution?

Step out into a north Indian city on a cold November morning and you will see a smudge of grey haze blotting out the rising sun. Walk along the bank of the Yamuna near Delhi or the Ganga at Varanasi and you will notice mats of foam, oily slicks and plastic floating downstream. Stand near a busy traffic signal and the noise meter on your phone may cross 90 decibels — the threshold beyond which long exposure damages hearing. These are not isolated experiences; they are everyday reminders that the air we breathe, the water we drink and the land we walk on have been progressively contaminated by our own activities.

Geography asks us to look at this contamination as a spatial problem — where it concentrates, why it concentrates there, and what its consequences are for human and ecological well-being. The NCERT chapter therefore opens with a clear definition that we will use throughout the lesson.

The four types do not exist in watertight compartments. Smoke from a factory chimney pollutes the air; the same smoke settles on fields as land pollution; rain washes the deposited residues into rivers as water pollution; and the constant rumble of the factory engine adds to noise pollution in the surrounding settlement. Geographers therefore study them together as a single environmental system under stress.

Table 9.1 — Types and Sources of Pollution

Source: NCERT, India: People and Economy, Class 12, Table 9.1.

9.1 Water Pollution — The Sickness of India’s Rivers

India has more than two dozen major rivers and an extensive web of canals, tanks, lakes and wells. None of these surface-water sources is, by itself, perfectly pure — rainwater always picks up small quantities of suspended particles, dissolved gases and organic matter as it flows over land. The natural water body has its own self-purifying capacity: micro-organisms, sunlight and dilution slowly break down or carry away small loads of contamination. The trouble begins when the load of pollutants becomes so heavy that this self-purifying capacity is overwhelmed. The water then becomes polluted — unfit for human, animal or industrial use.

The NCERT chapter is explicit on the cause: indiscriminate use of water by the increasing population and the expansion of industry has degraded the quality of India’s rivers, lakes and groundwater. Although natural sources such as erosion, landslides, decay and decomposition of plants and animals do contribute pollutants, the real worry is pollution from human activities — industrial, agricultural and cultural.

Sources of Water Pollution

Among these sources, the NCERT text underlines that industry is the most significant contributor. Most industrial wastes are disposed of in running water or lakes; the poisonous elements then reach reservoirs and rivers, destroying the bio-system of those waters.

Polluted Stretches of the Ganga and the Yamuna

The NCERT chapter highlights two of India’s most-revered and most-abused rivers. The Ganga^? turns visibly polluted downstream of Kanpur, gets worse downstream of Varanasi, and reaches its dirtiest stretch at the Farakka Barrage in West Bengal. The Yamuna’s short Delhi-to-confluence-with-Chambal section, and again near Mathura and Agra, are so degraded that the river is biologically dead in places.

Source: NCERT Table 9.2 — Sources of Pollution in the Ganga and the Yamuna Rivers.

Groundwater Contamination — Arsenic and Fluoride

Surface water is not the only victim. Two specific groundwater problems threaten Indian villages today:

• Arsenic contamination in the alluvial aquifers of West Bengal and Bihar. More than 38 million people across the Ganga-Brahmaputra delta are exposed to arsenic above the WHO limit, leading to skin lesions and cancers.
• Fluoride contamination in the hard-rock and arid belts of Rajasthan, Andhra Pradesh, Karnataka, Gujarat and Tamil Nadu, causing dental and skeletal fluorosis.

Water-Borne Diseases

Water pollution is a direct source of water-borne diseases. The diseases most commonly caused by contaminated water are diarrhoea, intestinal worms and hepatitis. The World Health Organization estimates that about one-fourth of all communicable diseases in India are water-borne — a number that translates into millions of preventable illnesses each year and a heavy load on the public health system.

9.2 Air Pollution — The Smog of Modern India

Air pollution^? is defined by NCERT as the addition of contaminants — dust, fumes, gas, fog, odour, smoke or vapour — to the air in substantial proportion and duration that may be harmful to flora, fauna and property. With increasing use of varieties of fuels as a source of energy, there is a marked increase in emission of toxic gases into the atmosphere. The three big sources are combustion of fossil fuels, mining and industries.

Major Air Pollutants & Their Sources

The combustion process releases several pollutants together. Each has its own pathway and its own health impact.

NCERT emphasises that air pollution causes various diseases related to the respiratory, nervous and circulatory systems. Smoky fog over cities — commonly called urban smog^? — is the visible form of this pollution. It is especially harmful to children, the elderly and people already suffering from asthma and bronchitis.

The Indian Air Pollution Story — In Numbers

The Indian Air Quality Index (AQI^?) translates concentrations of eight pollutants into a single number from 0 to 500. The bands are: Good (0-50), Satisfactory (51-100), Moderate (101-200), Poor (201-300), Very Poor (301-400) and Severe (401-500). Cities like Delhi, Lucknow, Kanpur and Patna routinely cross 300 in winter; on the worst nights, the index touches the ‘severe-plus’ band when farm-stubble burning in Punjab and Haryana, lower wind speeds and temperature inversion combine.

Why Delhi’s Winter Smog Is So Bad — A Geographer’s Reading

Why does north India choke every November? Geography supplies the answer. (i) The Indo-Gangetic Plain is a flat, enclosed basin between the Himalaya and the Vindhya, so pollutants get trapped. (ii) In late October the upper-air winds slow down and a temperature inversion forms — a layer of warm air sits above cooler surface air, preventing vertical mixing. (iii) Punjab and Haryana farmers burn paddy stubble in October-November, releasing large plumes of PM2.5 carried by north-westerly winds towards Delhi. (iv) Diwali firecrackers and the cold-season switch to space-heating add a final spike. The sum of climate, topography and human activity is a public-health emergency every winter.

9.3 Land Pollution — The Hidden Mountain

Land pollution happens when solids, liquids and gaseous pollutants are added to the soil. The NCERT chapter lists the chief pollutants as human and animal excreta, viruses and bacteria, garbage and the vectors that breed in it, pesticide and fertiliser residues, alkalinity, fluorides and radioactive substances. The sources are improper human activities, disposal of untreated industrial waste, and the over-use of pesticides and fertilisers in agriculture.

Three new categories of land pollutants have grown rapidly over the last two decades:

9.4 Noise Pollution — The Pollution You Can Hear

Noise pollution is ‘the state of unbearable and uncomfortable noise to human beings caused by sound from different sources’. The matter has become a serious concern only in recent years, due to a variety of technological innovations. The NCERT chapter identifies the main sources as factories, mechanised construction and demolition works, automobiles and aircraft. To these are added the periodic but polluting noise of sirens, loudspeakers used in festivals and community programmes.

The level of steady noise is measured by sound level expressed in decibels (dB). Of all the sources, the biggest nuisance is the noise produced by traffic, because its intensity and nature depend on the type of aircraft, vehicle, train, the condition of the road and the condition of the vehicle itself. In sea traffic, the noise is confined to the harbour due to loading and unloading activities. Industries cause noise pollution with varying intensity depending on the type of industry.

Indian Noise-Pollution Standards (CPCB)

Source: CPCB Noise Pollution (Regulation and Control) Rules, 2000.

Noise pollution is location-specific. Its intensity declines with distance from the source — an industrial estate, an arterial road or an airport. It is therefore particularly hazardous in the metropolitan and big cities of India where land-use is mixed and residential colonies often abut highways or factories.