Shanghai is one of the four municipalities under the direct administration of the central government of China, the largest city in China by population, and the second most populous city proper in the world, with a population of more than 24 million as of 2017. It is a global financial centre and transport hub, with the world's busiest container port. Located in the Yangtze River Delta, it sits on the south edge of the estuary of the Yangtze in the middle portion of the East China coast. The municipality borders the provinces of Jiangsu and Zhejiang to the north, south and west, and is bounded to the east by the East China Sea.