The study looked at how cities in China are growing and spreading out. They used data from 654 cities over 10 years to see how population growth and urban sprawl are connected. Most cities are spreading out quickly, while only a few are growing in a balanced way. Smaller cities are expanding their land, while bigger cities are growing in population. Some cities are actually getting smaller because people are leaving and the land is shrinking. Cities with shrinking populations are mostly in the eastern part of China.