Urbanization means an increase in the proportion of people living in urban areas compared to rural areas. An urban area is a built-up area such as a town or city. A rural area is an area of countryside.
Urbanisation can cause problems such as transport congestion, lack of sufficient housing, over-rapid growth and environmental degradation. Many cities display particularly sharp inequalities in housing provision, health and employment.
Some people try to escape these problems by moving away from the city - a process called counter-urbanisation. Long term, however, the solution must be to make cities more sustainable.