No decade in history has experienced such an increase in urban population as the last. From Tokyo-Yokohama, the world's largest urban area (population: 37 million) to Godegård, Sweden, which may be the smallest (population: 200), urban areas added 700 million people between 2000 and 2010.
Nearly one in 10 of the world's new urban residents were in the fastest growing metropolitan regions (see: Definition of Terms used in "The Evolving Urban Form" Series), which added nearly 60 million residents. They ranged from a an estimated increase of more than 8.5 people in Karachi (Note 1) to 3.9 million people in Mumbai (Figure 1). The average population growth in these 10 metropolitan regions was 6 million, approximately the population of Dallas-Fort Worth or Toronto, which were fast-growers on their own in comparison to other high income world cities.