The residential environment probably has the most profound impact on human health, behaviour and satisfaction, since this is where people spend the greatest part of their lives, rear children and develop social habits. Although decent shelter is a major human need, the current housing picture contains enormous deficiencies all over the world. More than a million people live in appalling housing conditions and there is a formidable global shortage of desperately needed dwellings. This situation is likely to worsen over the period ahead.
Mere statistics fail to capture the true dimension of the urban residential crisis. At the community level, the crisis is aggravated in many countries by a growing polarization of the population according to the location and quality of their houses. Although overall living standards have risen in most countries over the past decade, the supply of housing to low-income families remains far too small. The urban poor also bear the greatest burden of the mismanagement of the urban environment, as it is in the poorer areas that essential services are of the lowest standard. The residential crisis looms largest in the metropolitan areas of the less industrialized countries, resulting in scattered housing developments, mixed land uses, high rents, overcrowding and clandestine land occupancy.
In 1996, the UN Centre for Urban Settlements (Habitat) estimated that conservatively 20 percent of all human beings, about 1.4 billion people, lived under inadequate housing conditions. Depending on national concepts of adequacy, this figure could easily be twice as high. All estimates point out that, unless dramatic and determined measures are taken immediately, the situation is likely to deteriorate further, and not only in those countries whose economies are currently performing below required levels of investment, production and trade.
Housing conditions still leave much to be desired in most countries of the world, especially for the rural and the low-income urban groups. This is particularly true in the less developed countries, especially in regard to the necessary supporting infrastructure, especially sanitation, clean water, toilet facilities and sewerage. Population growth, and particularly the increase in urban areas caused by natural population growth and the exodus from the rural areas, has made the housing situation of the less developed countries much worse than it was 10 years ago. In the early 1990s, more than 600 million people in the urban areas of developing countries were living under life- and health-threatening conditions.
In most developing countries, less than two houses per thousand inhabitants are being built annually; some countries are building at less than 10% of their requirements. In Latin America and Asia the housing deficit is over 100 million units. The problem of housing and increasing population is especially grave in the urban areas, where 33% of the world's population lives. By the year 2000 51% will be in urban areas. In Africa alone, population growth as a whole is estimated at 2.4% per year, but the urban population is increasing at 5% per year. By the year 2000, it is estimated that 30% of Africa's population will be urbanized. Investment in new housing construction is less than half of what is required, which may run to 5% of the national income in some countries. The total funds required has tended to discourage realistic approaches to the shelter problem.
Some of the reasons for the current state of affairs are closely linked to: (a) lack of commitment and capacity to implement national and local sustainable social and economic policies, strategies, programmes, plans of action and projects; (b) poverty and low incomes of many urban families has forced them to live and work in slums, where they rent very inadequate dwellings often built on illegally owned land; (c) rapid urbanization has crippled many local authorities and is aggravated by land scarcity and land grabbing' (d) inadequate services to residential land and the inability of urban infrastructure projects to keep pace with growing needs and local authority capacities; (e) lack of housing finance for other than high and middle income groups; (f) failure of building materials and building services sectors to provide for the needs of those outside the middle and high-income groups; (g) unsuitable building and planning codes and excessive standards which prohibit realistic housing and human settlement projects for the urban poor; (h) failure to encourage community participation in low-income housing projects.