Over the last quarter-century, the number of urban dwellers in South Asia has more than doubled to almost 500 million. In India alone, the number of city dwellers has grown by 122 million. Delhi, Karachi, Kolkata and Dhaka have all joined Mumbai in the league of mega-cities. And yet, urbanization in South Asia has barely begun. With about 30% of its population living in cities, South Asia is the least urbanized in the world. But in the 20 years to come, South Asia will urbanize faster than any other region of the world, with the exception of East Asia. This rapid urbanization can be a powerful engine in accelerating poverty alleviation. But most cities in the region are struggling to cope with even the current level of urbanization. Can South Asian cities support the growing urban economy and population and become centers of shared prosperity, or will they become centers of grief?