OVER the next two decades, nearly all of the world's net population growth is expected to occur in urban areas, with about 5.6 million people (more than the population of Singapore) added each month. Today, only one-third of Asean's population is urban - still well below the proportion in North America, Western Europe, or Latin America - but this is changing fast. An additional 90 million people are forecast to move to cities in Asean by 2030.

Already, Asean's cities generate around two-thirds of its GDP, and the rapid urbanisation to come will be a crucial driver of economic growth in the region. In fact, no country has ever climbed from low-income to middle-income status without a significant population shift to cities. This is because larger cities generate scale benefits for economies, and wages are typically higher as people shift from farming to urban manufacturing and services. But urbanisation also generates major challenges to inclusiveness, health, efficiency, and the environment.

Many of Asean's cities are already straining under the pressures of rapid growth. In Indonesia and Vietnam, as many as 60 per cent of urban dwellers live in substandard housing. Congestion chokes the megacities especially; in Metro Manila, the average daily commute time is two hours, but that can easily stretch to four hours during the monsoon.