In 2012 the number of city dwellers in China passed the number of Chinese living in the countryside for the first time in history.  By 2020, the Chinese Government is planning on the urban population to be 60% of the total Chinese population. (By way of contrast, according to the World Bank, urbanisation in the USA is about 82%, the UK is about 80% urbanised and India is about 31% urbanised.)
This increased urbanisation has of course led to the growth of cities, and certain Chinese cities are becoming very large indeed.  Beijing passed 21 million people last year and Shanghai is now home to about 24 million people.  These “Supercities” are now being viewed as problematic by the Chinese government and are being targeted by new regulation. According to the AFP, the Chinese President Xi Jingping has promised to impose strict limits on population growth in the country’s “largest cities”. 

“Authorities will ‘strictly control the size of the population in especially large cities’, Xi said at a meeting of a Communist Party policy group, the official Xinhua news agency reported.” On the other hand, towns and small cities will have urban registration restrictions “fully liberalised” and middle-sized cities will have restrictions relaxed.
This restriction is the “hukou” household registration system, “which denies countryside residents equal access to health, education and housing benefits when they move to cities”.
So at the moment there is a fairly draconian system that limits internal movement of people from the country to cities in China. What the Chinese Government is proposing is that this system be abolished or liberalised for movements to the smaller urban centres and tightened for movements to the larger cities. The plan is lacking in detail at the moment – there is no timeline for these changes to come into place, nor are there any details as to what is and what is not a “large city”.  Nor is this change in the hukou system likely to be uncontroversial:

“Reforms to the hukou system have long been opposed by local governments and urban residents reluctant to shoulder the costs of extra benefits for migrants.” These proposed changes in China I think are interesting for two reasons. First they underline the fact that in so many ways the life of the average Chinese person is severely restricted by the Government. Second, they show that the concentration of a population into large urban areas is a worldwide phenomenon. Although in no ways a large city by world standards, Auckland (where I live) is surely unique in the proportion of the country’s population who live here. At the moment, Auckland is home to about a third of all New Zealanders. (I can’t think of another city in the world that is so predominant in its country – maybe Buenos Aires is the closest?) This places a demand on housing and infrastructure that is becoming more acute every year. At the same time, many rural and smaller centres are slowly dying as young people move to the cities (mainly Auckland). I can’t imagine a New Zealand government anytime soon cracking down on internal migration like the Chinese Government is doing, but perhaps restrictions on where external immigrants live could be a way to ease the pressure on Auckland’s population growth while at the same time increasing the smaller centres.  Of course, these smaller centres need to have the jobs and industry to support more people. At the moment, that is a problem – all the jobs are in Auckland!