Citizens get on a free-of-charge pure electric bus 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. (Xinhua/Hou Jun)