Environmental Pollution | Class 12 Geography Notes

Environmental Pollution

Environmental pollution is defined as the release of substances and energy from waste products of human activities into the environment. These pollutants cause degradation of natural resources and harm to living organisms. Pollution is classified based on the medium through which pollutants are transported and diffused. The four main types of pollution are air pollution, water pollution, land pollution, and noise pollution. Each type affects different components of the environment and has distinct sources and impacts.

Water pollution arises primarily due to indiscriminate use of water resources by increasing population and industrial expansion. Surface water from rivers, canals, and lakes naturally contains small quantities of suspended particles and organic and inorganic substances. However, when the concentration of these substances increases beyond the self-purifying capacity of water bodies, water becomes polluted and unfit for use. While natural processes such as erosion, landslides, and decay of plants and animals contribute to water pollutants, human activities are the major concern. Industrial effluents, agricultural runoff containing pesticides and fertilizers, and cultural activities such as pilgrimage and tourism significantly contribute to water pollution. Industries like leather, pulp and paper, textiles, and chemicals are major polluters, discharging untreated waste into water bodies. Agricultural chemicals infiltrate soil and groundwater, increasing nitrate content and contaminating water.

Water pollution leads to various water-borne diseases including diarrhoea, intestinal worms, and hepatitis. The World Health Organization estimates that about one-fourth of communicable diseases in India are water-borne. Rivers like the Ganga and Yamuna are heavily polluted due to industrial and domestic waste discharge from cities along their course. To address this, the Government of India launched the National Mission for Clean Ganga and the Namami Gange Programme aimed at reducing pollution through sewage treatment, industrial effluent monitoring, riverfront development, afforestation, and public awareness.

Air pollution is the addition of contaminants such as dust, fumes, gases, smoke, and vapour into the atmosphere in harmful proportions and durations. The combustion of fossil fuels, mining, and industrial processes release oxides of sulphur and nitrogen, hydrocarbons, carbon monoxide, lead, and asbestos into the air. These pollutants cause respiratory, nervous, and circulatory diseases. Urban smog, a smoky fog over cities, is a visible effect of air pollution. Acid rain results from air pollutants dissolving in rainwater, lowering its pH and causing environmental damage.

Noise pollution refers to excessive and harmful noise levels caused by industrial activities, transportation (aircraft, automobiles, trains), construction, and community events. It is measured in decibels (dB) and is location-specific, with intensity decreasing with distance from the source. Traffic noise is the biggest contributor to urban noise pollution. Noise pollution affects human health by causing stress, hearing loss, and disturbance to daily life.

Urban waste disposal is a growing concern due to rapid urbanization and population growth. Solid waste includes household garbage, industrial waste, plastics, glass, metals, and other discarded materials. Improper disposal leads to health hazards by attracting disease vectors like flies and rodents and causing foul smells. In many Indian cities, a significant portion of waste remains uncollected, accumulating in open spaces and streets. Industrial waste dumping into rivers further exacerbates water pollution. Sustainable waste management involves treating waste as a resource for energy and compost production.

Rural-urban migration driven by economic opportunities in cities leads to rapid urban population growth. Migrants often settle in slums due to unaffordable housing. Slums are characterized by overcrowding, poor sanitation, lack of basic amenities, and health hazards. The Swachh Bharat Mission aims to improve urban sanitation and living conditions in slums.

Land degradation results from natural processes and human activities such as soil erosion, waterlogging, salinisation, and deforestation. It leads to reduced agricultural productivity and can convert productive land into wasteland. Watershed management programmes involving community participation have been successful in areas like Jhabua district in Madhya Pradesh to restore degraded land and improve livelihoods.

📊 Diagram: Fig.9.1 shows a boat rowing through a thick layer of foam on the heavily polluted Yamuna river near New Delhi, illustrating water pollution caused by industrial and domestic waste.

🔗 Connection: Leads to detailed sections on specific types of pollution: Water Pollution, Air Pollution, Noise Pollution, and Urban Waste Disposal.