The blue book proposes that reforming the household registration system is now an urgent necessity. The long-standing household registration management system and policies for controlling construction land have resulted in, while there has been growth in industries and employment population in industrial gathering areas, the family living situations of the employed population have not urbanized in tandem. This has led to urbanization relatively lagging behind industrialization. Once there is an economic crisis or shrinking demand in industrial sectors, the urban economy will fall into catastrophic depression, especially for the workers who are mainly migrant workers.
Criteria for Dividing Super Large Cities and Mega Cities? List of 39 Super Large Cities in China from "City Blue Book"
http://budai.me/info/?action-viewnews-itemid-3674
List of Super Large Cities in China, City Blue Book