Urban living is becoming increasingly predominant, with 55% of the world’s population currently living in cities and 68% projected to do so by 2050 (1). While megacities with more than 10 million inhabitants command much attention, they account for less than 10% of the world’s urban population. In contrast, nearly half of all urban residents – over 2 billion people – live in cities with populations under 500,000 (Table 9.1). It is in these smaller cities where population growth rates tend to be highest. The USA, Latin America, and Japan are very highly urbanized but both Africa as a whole and India remain well below 50% urbanized (Figure 9.1). Many low- and lower-middle-income countries in particular are projected to urbanize rapidly in coming decades, with a projected increase of 2.5 billion people in urban areas by 2050 – accounting for essentially all projected human population growth through mid-century.