Slums are not a new phenomenon. They have been part of the history of most cities, particularly in the early years of urbanisation and industrialisation as populations boomed. Slums are generally the only type of settlement affordable and accessible to the poor in cities, where competition for land and profits is intense.
There are two main reasons why slums develop: population growth and governance.
Population growth
Countries around the world are urbanising rapidly as more people migrate from rural areas to the cities and natural population growth continues to occur. Today, more than half the world’s population resides in urban areas. More than 90 percent of this urban growth is taking place in the developing world.
Urban migration happens for a number of reasons:
The pushing and pulling forces of migration. Some people migrate because they are pushed out of their place of origin by factors such as natural disasters or sustained ecological changes. Others are pulled to a new destination by better job prospects, education, health facilities, or freedom from restrictive social or cultural realities.
Low incomes from agriculture. Most people in rural areas work in the agricultural sector, which is highly dependent on weather. Also, rural land is limited, its fertility sometimes low or declining, land holdings are small, farm debts are high, and many households have become landless. As a result, overall rural incomes are low.
Better job prospects. In comparison with rural areas, urban areas offer dramatically increased job opportunities. In addition, because urban cultures are often less constrained than those in villages, cities can also offer greater prospects of upward social mobility.
People know what cities can offer them. Most migrants make a deliberate choice to stay or leave in rural areas. Improved transport, communications and links with earlier migrants have all made rural populations much more aware of the advantages and disadvantages of urban life, especially regarding job opportunities and housing.
Urban migration is often a survival strategy for rural households. Sometimes, rural households split into several groups located in different places—rural areas, small towns, and big cities—in order to diversify their sources of income and be less vulnerable to economic downturns.