Megacity Tianjin plans for another five million
22 June 2011 Last updated at 04:23 BST
More than 160 cities in China boast populations of one million or more - and on top of that there are five urban areas with more than 10 million residents.
Tianjin is one such area, with 13 million people living there, and another five million are expected to move in over the next 10 years.
Martin Patience reports from Tianjin.