For my perspectives, the large presure of population is the greatest barrier in China.
In the process of the development of the urbanization, the scale of the city expands constantly and then population expansion, traffic congestion, environmental pollution.
A large number of city populations have to consume a lot of resources, which means the quality of environment will be reduced, includ green space being decreased, agricultural land being occupied, they have been used as commercial, industrial and residential land. Also water use and water pollution are serious caused by excessive consumptipn, industrial pollution. So it is very hard to implementing in China.