Rapid and uncontrolled urbanisation is evident across the majority of low and middle-income (LMIC) countries. This growth is particularly evident in South Asia where urban populations are projected to rise from 45 to 62 per cent by 2050. Yet, much needs to be done to respond to this scale of growth. The infrastructure—housing, sanitation, health care, education, fuel, electricity, roads—needed to support this expanding population is not adequately available, particularly for the poorest. For one third of the world’s urban population, 828 million people, this means living in slum conditions. These conditions are fuelling the deepening trend of inequities across a wide range of health and social outcomes.