Ningbo , formerly written Ningpo, is a sub-provincial city in northeast Zhejiang province in the People's Republic of China. It comprises the urban districts of Ningbo proper, three satellite cities, and a number of rural counties including islands in Hangzhou Bay and the East China Sea. Its port, spread across several locations, is among the busiest in the world and the municipality possesses a separate state-planning status. As of the 2010 census, the entire administrated area had a population of 7.6 million, with 3.5 million in the six urban districts of Ningbo proper.