2030, we would expect it to be one billion. One in eight people on Earth will live in a Chinese city. So they still need to do a lot more building. Miller predicts there will always be a huge demand for housing in China. The challenge will be making it affordable for the Chinese people. Zhengzhou's population boom According to city government statistics, the population in Zhengzhou grew by 30 % between 2000 and 2010, and today stands at close to nine million people, roughly the same population as New York City -LRB- 8.245 million in 2011 -RRB-, London -LRB- 8.174, 2011 -RRB- and Bangkok -LRB- 8.281, 2010 -RRB-. But the city appears to have physically grown even faster. In an area nearly twice the size of San Francisco, entire new districts of towers have sprung where 10 years ago locals say there were empty fields. Armies of construction crews are still hard at work. Dozens of new towers are in various stages of completion, even though real estate companies are still clearly struggling to fill some of the completed buildings. On a street corner, two female university students distributed advertising leaflets to passing drivers and held up a buy two floors for the price of one deal for a residential housing development called Harmony Building. In the office of another real estate development company, a sales representative told CNN all of the units in neighboring residential