Cities are constantly evolving and moving – sometimes with positive effects for residents and at other times with serious negative effects on human and environmental health, economic health and mortality rates.

Unhealthy smog levels and traffic jams (including an over-reliance on fewer but larger road networks), with their chorus of horns and shouts, are routine irritations of urban lives, and things could get much worse. The world’s cities are facing an urgent set of challenges when it comes to ensuring that…