For centuries, China has been the world's most populous country despite currently having one of the lowest population growth rates in the world (0.44%) due to family planning policies in place since the 1970's. These restrictions have also lead to the slightly skewed sex ratio of 1.06 males/ females because of a common cultural preference favouring sons over daughters.
Urbanisation has been a significant outcome of fast-paced economic development throughout the reform era as large 'floating populations' migrate away from traditional farmland in the west toward urban metropolises. This mass-scale movement has generated much political concern over rising population densities in receiving towns and cities beyond the limits of sustainability.