Tianjin is the largest coastal city in northern China. In terms of urban population, Tianjin is the fourth largest in China, after Shanghai, Beijing, and Guangzhou. In terms of administrative area population, Tianjin ranks fifth in Mainland China. The walled city of Tianjin was built in 1404. As a treaty port since 1860, Tianjin has been a major seaport and gateway to Beijing. During the Boxer Rebellion the city was the seat of the Tianjin Provisional Government. Under the Qing dynasty and the Republic of China, Tianjin became one of the largest cities in the region. At that time, numerous European-style
Water supply and sanitation in China built in the city of Nanjing. Subsequently, China engaged in what is possibly the largest wastewater treatment investment program in history. It has been estimated that in 2006 there was sufficient capacity to treat 52% of municipal residential wastewater. According to the State Environmental Protection Agency the rate of urban wastewater treatment reached 57% in that year. The government's goal to achieve a level of 60% for treatment of municipal wastewater by 2010 was surpassed. By 2010, 77.5% of domestic waste water was treated. Between 2001 and 2004, the number of cities that charge wastewater tariffs has increased from 300