<P> Many slums are part of economies of agglomeration in which there is an emergence of economies of scale at the firm level, transport costs and the mobility of the industrial labour force . The increase in returns of scale will mean that the production of each good will take place in a single location . And even though an agglomerated economy benefits these cities by bringing in specialization and multiple competing suppliers, the conditions of slums continue to lag behind in terms of quality and adequate housing . Alonso - Villar argues that the existence of transport costs implies that the best locations for a firm will be those with easy access to markets, and the best locations for workers, those with easy access to goods . The concentration is the result of a self - reinforcing process of agglomeration . Concentration is a common trend of the distribution of population . Urban growth is dramatically intense in the less developed countries, where a large number of huge cities have started to appear; which means high poverty rates, crime, pollution and congestion . </P> <P> Lack of affordable low cost housing and poor planning encourages the supply side of slums . The Millennium Development Goals proposes that member nations should make a "significant improvement in the lives of at least 100 million slum dwellers" by 2020 . If member nations succeed in achieving this goal, 90% of the world total slum dwellers may remain in the poorly housed settlements by 2020 . Choguill claims that the large number of slum dwellers indicates a deficiency of practical housing policy . Whenever there is a significant gap in growing demand for housing and insufficient supply of affordable housing, this gap is typically met in part by slums . The Economist summarizes this as, "good housing is obviously better than a slum, but a slum is better than none". </P> <P> Insufficient financial resources and lack of coordination in government bureaucracy are two main causes of poor house planning . Financial deficiency in some governments may explain the lack of affordable public housing for the poor since any improvement of the tenant in slums and expansion of public housing programs involve a great increase in the government expenditure . The problem can also lie on the failure in coordination among different departments in charge of economic development, urban planning, and land allocation . In some cities, governments assume that the housing market will adjust the supply of housing with a change in demand . However, with little economic incentive, the housing market is more likely to develop middle - income housing rather than low - cost housing . The urban poor gradually become marginalized in the housing market where few houses are built to sell to them . </P> <P> Some of the slums in today's world are a product of urbanization brought by colonialism . For instance, the Europeans arrived in Kenya in the nineteenth century and created urban centers such as Nairobi mainly to serve their financial interests . They regarded the Africans as temporary migrants and needed them only for supply of labor . The housing policy aiming to accommodate these workers was not well enforced and the government built settlements in the form of single - occupancy bedspaces . Due to the cost of time and money in their movement back and forth between rural and urban areas, their families gradually migrated to the urban centre . As they could not afford to buy houses, slums were thus formed . </P>

Paragraph about slums and their impact on society