By 2050 an estimated 2.5 billion more people will be added to urban areas, with 90% of this growth taking place in Africa and Asia. According to Nobel Prize winning economist, Paul Romer, this will mean the building of more urban areas in the next 100 years than currently exist today.

If managed effectively, Africa’s cities will drive the continent’s economic growth, and thereby help reduce poverty. To date, however, Africa has yet to realize the positive gains of rapid urbanization experienced elsewhere. Instead, increasingly concentrated populations have become a major stress on the limited infrastructure and services, such as housing, employment, health, education, and safety.
https://qz.com/africa/1740068/africa...-urbanization/