City dwellers, especially the most vulnerable, face numerous challenges in securing adequate nutrition, education, housing and other contributors to a healthy life.

Stresses caused by rapid urbanization are interrelated—lack of sanitation, air pollution, respiratory problems, communicable disease, accidents and injuries—and require holistic solutions.

Rapid urbanization puts tremendous pressure on water supply and sanitation systems. Water is a precious resource that needs to be conserved and also shared equitably.

The city is home to opportunities and risks; with better planning we can create safer cities, prevent injuries and save lives.

Poverty and prosperity coexist. The unreached may be only just around the corner, and need to be provided with information and access to health care.

With large populations competing for resources and space, issues of equity and inequality in the city are especially relevant to the lives of urban women and children.

Creative ways are being found to spread health information— whether on healthy lifestyles, diet, or the dangers of smoking and alcohol—to urban populations, particularly the young.

Intermittent water supplies compel people to store water in homes. Improper storage leads to breeding of disease-carrying mosquitoes, which can also breed in small amounts of water collected in discarded containers and tires.

A healthy city provides access to health services for everyone; this is a challenge with swelling urban populations that include migrants, casual labourers, and millions who live in encampments and unofficial dwellings.

Some of the problems of rapid, unplanned urbanization can be avoided by health-conscious urban design—building in “green” spaces and recreation areas that foster healthy lifestyles, from exercise to stress management.

The urban environment overlays the natural environment, raising issues of sustainable use and protection of land, water, air and soil. The management of this human–natural interface has a significant effect on the health of urban dwellers.

What are the limits of urbanization? Urgent action is needed to ensure healthy and sustainable environments for all citizens.