Cities are energetic hubs of creativity and power, learning and culture. They are ecosystems that support growth and change, and are now home to more than half of the world’s population – a proportion expected reach two thirds by 2050.

The World Health Organization (WHO) has identified urbanization as one of the key challenges for public health in the 21st century. It is typically discussed in negative terms, including infectious outbreaks, unhealthy lifestyles and environmental threats. Yet cities offer significant opportunities to improve public health through health-enhancing policies and actions.