 The brief calls for integrated sustainable urban planning and design to create a city as close to carbon-neutral as possible within economic constraints.Located in sensitive wetlands on Chongming Island at the mouth of the Yangtze River just north of Shanghai, Dongtan's first phase, a marina village of 20,000 inhabitants, will be unveiled at the 2010 World Expo in Shanghai.By 2020, nearly 80,000 people are expected to inhabit the city's environmentally sustainable neighborhoods.