Ningbo, also known as "Yong"（甬）in Chinese, is a city with independent economic planning status and a sub-provincial city in Zhejiang. It is an important port city on the southeastern coast of China and an economic hub of southern Yangtze River Delta. In the Tang Dynasty (AD 618-907), the city was called Mingzhou. In AD 1381, the city was renamed Ningbo, which means "calm waves" in Chinese, to reflect the saying "calm sea produces calm waves", and this name has been used ever since. There are six districts under Ningbo's jurisdiction: Haishu, Jiangbei, Zhenhai, Beilun, Yinzhou, and Fenghua; two county-level cities: Yuyao and Cixi; and two counties: Ninghai and Xiangshan. Ningbo covers 9,816.2 km² on land and 8,355.8 km² at sea. As of the end of 2022, Ningbo had a total of 9.618 million permanent residents.