Dongtan is a new eco-city planned for the island of Chongming, near Shanghai. The city should be open, with accommodation for 50,000, by the time the Expo 2010 opens in Shanghai. By 2040, the city is slated to be one-third the size of Manhattan.

Dongtan was recently presented at the United Nations World Urban Forum by China as an example of an “eco-city”, and is the first of up to four such cities to be designed and built in China by Arup, a British company. The cities are planned to be ecologically friendly, with zero-greenhouse-emission transit and complete self-sufficiency in water and energy, together with the use of zero energy building principles.
-from wikipedia