China's largest cities can feel like endless, sprawling landscapes of construction sites, tower cranes and crowded streets.
But are these mega-cities even bigger than we thought?
OECD researchers argue in a new report that many more people live in China's largest urban centers than previously estimated. Instead of six cities with more than 10 million people, they say, China has 15.
The researchers arrived at the larger numbers by ignoring traditional city limits, and instead using density measures and transportation patterns to define new municipal boundaries, or "functional urban areas."
The results are dramatic. Shanghai goes from a city of 22.3 million to one of 34 million. The population of Guangzhou, in southern China, more than doubles from 11.1 million to 25 million.
Related: Beijing's Growing Subway
Population data is exceedingly tricky to produce in China. One reason is the sustained wave of migrants workers moving from rural to urban areas. Millions make the switch every year, often without securing the proper household registration, or "hukou," which can leave them without access to social services.
Here's the full ranking of cities, and their estimated population:
- Shanghai (34 million)
- Guangzhou (25 million)
- Beijing (24.9 million)
- Shenzhen (23.3 million)
- Wuhan (19 million)
- Chengdu (18.1 million)
- Chongqing (17 million)
- Tianjin (15.4 million)
- Hangzhou (13.4 million)
- Xian (12.9 million)
- Changzhou (12.4 million)
- Shantou (12 million)
- Nanjing (11.7 million)
- Jinan (11 million)
- Harbin (10.5 million)
