As in other parts of the world, urban growth has led to profound transformation of the atmosphere, hydrosphere and biosphere. The increase in the size of urban areas, for example, has affected the local climate.
The rapid development and expansion of industries and in the number of motor vehicles and machines have led to increased pollutant emissions affecting air quality, health and the biosphere.
Construction and infrastructural works have modified the how of rivers, greatly increasing the incidence of flood hazard, causing erosion and slope failures, and involving enormous government expenditure.
Causes of Environmental Degradation
Urban growth has been largely generated by a rapid increase in population. The consequence of such rapid urbanization is the inability of the authorities to provide adequate infrastructural facilities and services to keep pace with population growth.
This results in the growth of urban slums and squatter settlements, and the overburdening of the water supply, sewerage and waste-disposal systems, thus, resulting in environmental degradation.
Another important factor is urban poverty. Generally, this is defined as a level of well-being below the minimum needs of a household in terms of nutrition, clothing, housing, sanitation and basic requirements.
Squatter settlements are generally found along river banks and railroads, or on disused mining land, and other undeveloped government or even private land.
While there are some good-quality dwellings in the squatter settlements, most of them are somewhat substandard, being constructed from wood, corrugated iron and even cardboard.
The majority do not have proper water and electricity facilities or sewage-disposal systems. Domestic waste is generally dumped either near the settlements or on river banks, further exacerbating environmental degradation in urban areas.
Urban areas are often centers of industrial activities. Many of the industries are resource-based, although integrated metal-processing, and chemical and petrochemical industries have also been established.
While industrialization has brought some measure of economic prosperity and increase in standards of living, it has also resulted in natural-resource depletion in the form of air, water and noise pollution and the accumulation of toxic and hazardous wastes, all of which affect human health and the quality of life.
Transport is another major source of environmental degradation in urban areas. Apart from lead pollution, particulates and carbon monoxide (CO), the increased number of motor vehicles is also responsible for a special form of atmospheric pollutant-the photochemical smog.
The deterioration in air quality, together with increases in potentially polluting activities, is indeed a cause for concern in these cities.
In conclusion, several causes of environmental degradation in urban areas have been shown such as high population, poverty, slums, means of transportation, industrial activities etc.