Dongtan, Shanghai

Dongtan was a planned development described as an eco-city on the island of Chongming in Shanghai, China that was never built. Design began in 2005, and by 2010 the development had stalled. Adjacent to booming Shanghai, designers claimed Dongtan would be the world's first truly sustainable new urban development. Dongtan was presented at the United Nations World Urban Forum by China as an example of a purpose-built eco-city.

Reasons for the project's closure include its proposed location in a highly-value wetlands area, tensions between its development partners (Arup, a British engineering company, and Shanghai Industrial Investment, a state-owned developer), and loss of political support (due to the jailing of Dongtan's top political backer, former Shanghai Communist Party chief Chen Liangyu, on corruption charges in 2008).

The project has been described as a failure because it was not built. However, as an example of design it has inspired and informed other cities worldwide. Ideas from Dongtan were incorporated into the renovation of the Chongming District as a net zero island. Dongtan became a model for a subsequently planned eco-city outside Tianjin.