As the world has transformed, so have cities. Today, cities are home to 54 percent of the world’s population, and by the middle of this century that figure will likely rise to 66 percent. According to the United Nations (UN) Habitat I (1972), Habitat II (1996) and Habitat III (2016) summits, cities are facing many serious challenges, including growing inequality, security concerns and the worsening impacts of climate change. Uncontrolled urbanization has led to many problems (haphazard growth of areas, emergence of slums, inadequate water and power supply, poor sanitation, shortage of transport and other civic amenities, shrinking green spaces, pollution, crime, and urban disaster risks such as fire, flood, road and industrial accidents, etc.).