Chongming, an island at the mouth of the Yangtze river, has felt the impact of environmental degradation more than many places, as its population has doubled in 50 years and deforestation has silted up the river.

Now Chongming is to become a model for environmental good practice. The Shanghai government has just begun construction of an “eco-city” at a place called Dongtan, which is to be a showcase for sustainable urban life in a country where 20m people are moving to cities every year.