Cities aggregate people, industry and capital, so they are influential but vulnerable. They depend on distant sources of food, water and energy, have fragile drainage and waste systems, are prone to health risks from pollution and disease and are mostly coastal and exposed to sea-level rise. In the late 1990s Danida began a spectacular demonstration in the urbanising, heavily polluted Kathmandu Valley of how to build environmental awareness, set environmental standards, and encourage cleaner production and energy efficiency in partnership with business, and how to improve air quality. A ‘palace coup’ ended it in 2005, with terrible consequences for air quality, but it had already shown that it was possible to respond to an environmental emergency through many interlocking actions that must all be done at once or none will work – a model for the climate change response. The experience offers insights that are explored in other cities, highlighting the importance of self-organising neighbourhood networks in seeking and planning for liveable cities, and in disaster preparedness. These networks have immense value to local governments in making urban systems stronger and more resistant to climate chaos.