People dine at a restaurant with robot servers in the Sino-Singapore Tianjin eco-city in Binhai New Area, north China's Tianjin, Dec. 19, 2018. The Sino-Singapore Tianjin eco-city, inaugurated in 2008, is an intergovernmental cooperation project designed to strengthen environmental protection, conserve resources and build a harmonious society. The eco-city is expected to be a model for other cities in China. [Photo/Xinhua]