[bpolverini]

Partly, but it is primarily to bring those living in rural areas into an urban context as a mechanism for modernizing the economy.

Right now, under the hukou system (https://en.wikipedia.org/wiki/Hukou_system), you can't just move anywhere you want. What ends up happening is those living in rural areas illegally move to cities like Beijing/Shanghai/Shenzhen for work, but can't get their children educated or get healthcare. This is a way to prevent mass migration to the first-tier cities.