Posted: 26 September 2007

Rapid, unplanned urbanization can be an important source of health problems. By 2007, urban dwellers for the first time in history outnumbered those in the traditionally rural areas. The urban population of the developing world - already over 2 billion - is set to double by 2030.

City squalor. Credit: UN-Habitat
City squalor. Credit: UN-Habitat
City squalor. Credit: UN-Habitat
  • While urban living conditions may bring improvements in terms of access to health care, education, sanitation and clean water, this potential is often not realised, especially for poorer new migrants, who may suffer from overcrowding, pollution and dangerous working conditions.

  • Infectious diseases such as TB spread more easily and more rapidly in overcrowded conditions, while road traffic collisions and other forms of violence are also more frequent in urban settings. Stress and poor living conditions can also cause health problems.

  • Increased exposure to biological and chemical health risks is particularly harmful to children. Children suffer the greatest number of deaths due to diarrhoeal diseases (2.5 million deaths per year) and this number is likely to increase in populations of the urban poor. Asthma, often made worse by urban air pollutants, has also increased among children.

  • In sub-Saharan Africa the proportion of urban residents in slums is highest at 71.9 per cent, but in numbers alone, Asia accounts for some 60 per cent of the world's urban slum residents.


The Challenge of the Slums, UN-Habitat, 2003.