In many poor countries, overpopulated slums exhibit high rates of disease due to unsanitary conditions, malnutrition, and lack of basic health care. Many countries in the developing world neither have the legal nor the financial capacity to deal with the rapid growth of mega cities.
Approximately one-sixth of today's world's population now live in shanty towns, which are seen as "breeding grounds" for social problems such as crime, drug addiction, alcoholism, poverty and unemployment.
The process of urbanisation presents enormous challenges to governments, social and environmental planners, architects, engineers and the inhabitants of the megacities. Just one example: The London population grew from one million to eight million people in 150 years, while the population of Mexico City grew from one million to over 15 million people in only 50 years.
No wonder, that the increasing number of people living in cities creates demand, in areas such as housing and services. The destruction of our environment and poverty are two other concerns, which city administrations have to take care of, as especially the poor do not have the necessary financial background to tackle these problems.
Megacities influence a variety of living conditions for citizens. Although traffic jams, poor air quality and increasing health risks, make life in megacities more difficult, people continue to choose to live there. Therefore it is essential, that more government programs are implemented in order to help improve living conditions for the inhabitants of metropolitan areas.
Nevertheless, megacities also offer great chances: according to the OECD Mexiko City and São Paulo produce around 50% of the income of their countries. Bangkok contributes more than 40% to the GDP, although it is home only to 10% of the population of Thailand.