This essay throws light upon the four main environmental problems of urbanisation. The problems are: 1. Urbanisation and Water Pollution 2. Urbanisation and Air Pollution 3. Urbanisation and Amenity 4. Health Impact of Urbanisation.
Environmental Problem # 1. Urbanisation and Water Pollution:
Most large cities are situated next to important water resources. It is difficult to name a large urban area not contiguous to some important body of water. The proximity of cities to water resources is, of course, no accident.
Water transport and travel have historically been cheap relative to overland alternatives. Cities naturally developed first as entre-pots for water based transportation, and in many cases, later expanded as industrial centres as well.
The water adjacent to most major cities in the world are currently badly polluted. The waste disposal function of water resources has been chosen by the society in almost every instance where it conflicts with the recreational or amenity function. Pollution has occurred largely by default—for lack of an effective social decision to halt polluting activities.
Economists do not agree unanmiously that water pollution is an urban environmental problem per se. In fact, some even argue that the social costs of water pollution outside urban areas are greater than the social costs of urban water pollution.
The first point to recognise is that the social costs of water pollution in a hypothetical less-urbanised society than our own would not necessarily be less than the costs we now actually incur.
Assuming a given degree of industrialisation and a given level of technology, the main advantage of a less-urbanised society over our own would be the technical circumstance that the natural self-cleansing abilities of bodies of water are generally more effective if the amounts of pollutants are low relative to the amount of water in a given area.
For example, little pollution may result if 100 factories emit pollutants into a river over a 200-mile stretch of water. But if the same 100 factories are all located within a 1 – mile length of the same stream within a city, pollution may become a serious problem.
The importance of this technical point will, of course, vary greatly with the characteristics of different water resources and with the type of pollutant.
We conclude that the main direct impact of urbanisation within a modem industrialised society on the social cost of water pollution is the result of concentration of pollutants within a relatively small geographical area. But this point does not settle the question at issue. On the other side are some cogent arguments that urbanisation is not a fundamental cause of water pollution.
First, it is not clear that a given amount of damage to water resources in urban areas involves the same degree of external costs of society as it does in rural areas. On the contrary, concentration of water pollution damage downstream in urbanised areas may result in significantly less foregone social benefits than if the damage were spread evenly throughout a whole river basin.
The benefits forgone because of water pollution in urban areas seem to be limited for the most part to aesthetic considerations, or loss of amenity, and to increased travel costs. Good substitutes for the water resources mediately adjacent to cities are often available for recreational and drinking water purposes, provided that upstream (rural) water resources remain relatively unpolluted.
That is, transportation costs for city people to rural recreational water resources and for rural drinking water supplies to city people may be low relative to the costs of pollution prevention or pollution damage avoidance in the cities, themselves.
Moreover it may be socially more efficient to transform polluted water into safe drinking water by conventional treatment methods than to prevent the pollution in the first place.
Some evidence indicates that treatment costs for municipal and industrial uses are relatively insensitive to the degree of water pollution over wide range of pollution concentrations. Thus, the greater concentration of pollution in urban areas may be relatively unimportant in affecting the treatment costs required to produce economically useful water.
A closely related point is that if society does choose to treat water discharges into water resources, they are likely to be significant economics of scale in water treatment processes if the sources of pollution are highly concentrated in urban areas.
All of these points suggest that under some circumstances spreading a given amount of pollution evenly over a large area is not obviously better than concentrating it in just a few locations and leaving most of the area relatively unpolluted.
Finally, as we have already observed, some urban recreational uses of water-boating, in particular are apparently compatible with a high degree of water pollution. Again, the doubtlessly some unknown degree of loss of amenity when people have to swim or boat in the middle of beds of algae and industrial wastes.
Treated drinking water is not necessarily the same thing aesthetically as untreated water, and this difference, too, has to be recognised in assessing the full social costs of water pollution. More generally, the fact that people have to live in close proximity to foul- smelling and fitting water clearly diminishes the amenity of urban life to some extent.
On the whole, these points suggest that water pollution as a social problem may not be primarily a result of urban agglomeration, even if the deterioration of water resources is most evident in the vicinity of cities. On the other hand, none of these points justify the conclusion that water resources in urban areas are sufficiently clean today.
The important issue is, however, whether the social policy mix of water quality control measures should include any of a number of governmental measures to discourage urban agglomeration or whether government efforts should be confined to the more direct measures.
Environmental Problem # 2. Urbanisation and Air Pollution:
Air pollution, tube water pollution, is most evident in urbanised areas. The arguments we have just gone through for the problem of water pollution showed that this fact by itself does not suffice to identify the factor of urbanisation as the fundamental cause of air pollution.
Let us again perform the conceptual experiment of comparing air pollution in our economy with the same problem in a hypothetical economy that is significantly less urbanised than our own but is otherwise identical in every respect.
As a first approximation, the total quality and composition of pollutants emitted into the atmosphere could be taken to be identical in this comparison. Following our argument in the case of water resources, it seems reasonable to point that only the relative dispersion of pollutants would be effected by differences in the concentration of people and industry in urban agglomerations between the two economics. The social costs of air pollution are clearly greater in our own society than they would be in hypothetical less-urbanised economy.
Just as in the case of water pollution, the concentration of air pollutants is an important factor in determining how well the natural processes of the air can cleanse themselves in a given area. But, in sharp contrast to the case in water, dispersion of air pollutants is probably all-important in determining the total social costs of a given level of air pollution emissions.
Unlike water pollution, air pollution in a small area results in significant social costs because man has not yet discovered any good, relatively cheap substitutes for clean air in the cities where he must live and work. Low concentrations of many gases or particles in the atmosphere seem to have virtually no harmful consequences to man, but high or chronic concentrations can have all the insidious, economically damaging effects.
People can avoid unclean air in cities only by very costly expedients of commuting long distances to work, quitting their jobs, or purchasing air filtration systems for their homes and venturing outside as little as possible. Therefore, public policies affecting population concentrations seem, on first consideration, to have a significant role to play in minimising the net social costs of air pollution.
Environmental Problem # 3. Urbanisation and Amenity:
Urbanisation necessarily involves the crowding together of people in small areas. The resulting congestion produces a special kind of external cost, which differs in one fundamental respect from the external costs of water pollution or air pollution. The latter kind of externality results from individuals or firms emitting waste products into socially owned environment media.
The externality is non- reappraisal, the victims of air and water pollution do not inflict external costs back on the polluter. In contrast, congestion in cities involves reciprocal external costs.
People and goods simply get in each-others way, and everybody is a loser. For example, when 1000 automobiles are crowded together on a city street built to accommodate only half that number, every one of the 1000 drivers inflicts congestion costs on the other 999.
All 1000 share responsibility for the externality, equally and all bear the cost according to how much they value the time they lose waiting for the traffic jam to clear. Other external costs directly associated with congestion in cities include the noise, dirt and hectic pace of modern life.
Beyond the relatively straightforward problem of congestion costs, virtually nothing of objective validity can be said about the connection between degree of urbanisation and the general level of amenity in a society High densities of population and industry in cities inevitably lead to all sorts of externalities, both good and bad.
In Chennai, for example, one man’s activities impinge on another man’s welfare to the maximum degree possible in this country. When Mr. X plays his radio in Chennai, Mr. Y, in the adjacent house, listens whether he wants or not. Mr. X and Mr. Y litter the streets at each other’s expense, and they constantly are in each other’s or somebody’s way during rush hours.
Compared to Chennai, the pace of life is slower and more relaxed in less densely populated areas, and certainly smaller towns are cleaner and quieter. Some evidence exists that the extent of mental illness in New York is astoundingly high, and some people would ascribe this fact to the dis-amenity of life in an overcrowded metropolis.
These observations tempt us to conclude that high levels of urbanisation cause much of the dis-amenity of modem life.
Environmental Problem # 4. Health Impact of Urbanisation:
Virtually all governments in developing countries have failed to ensure that rapid urban growth is accompanied by the investment needed in the infrastructure and services, especially in residential areas with a predominance of poorer households. Few governments have given priority to increasing the power, resources, and trained personnel of the city and local authorities that have to cope with rapid urban growth.
The result has been a rapid increase in the number of people living in very overcrowded conditions and in illegal or informal settlements. Inadequacies in the water supply, sanitation and other parts of infrastructure and services are the health and environmental implications of overcrowding.
The in adequacies may be more the result of the illegal nature of the settlements than of the lack of resources available to local governments and of the capacity of the inhabitants to pay the cost.
In most small urban centres and many of the cities in the poorest developing countries, the proposition of people living in illegal settlements may be smaller partly because the market in land is less commercialized.
In addition, in many of the least urbanised countries traditional and land tenure systems limit the rights of the individuals to own, buy, and sell land, and this has made it easier for poorer households to obtain land for housing.
Despite the fewer numbers of people living in illegal settlements in such urban centres, the proportion living in areas with inadequate or no provision for an infrastructure and services may be as high or higher than in the largest cities in richer developing countries, the inadequacies stemming less from their illegal status, and more from lower income and weaker local governments.
Another aspect of urbanisation with important health implications is the association of urban expansion with disease. The expansion of the built-up area, the construction of roads, reservoirs, and drains, land clearance, and deforestation may effect drastic changes in the local ecology.
Natural foci for disease vectors may be trapped within the urban extension and new ecological riches for zoonotic animal reservoirs created. Within conurbations, synanthropic animal and anthropoid sector populations may adopt to a new habitats and introduce fresh infections to spread among the urban population.
For instance, in India, where the vector of sympathetic filanasis is a peridomestic mosquito, there has been rapid increase in the incidence of the disease and in the vector population, associated with the steady rise in the growth of human populations in endemic areas.