In "one of the most ambitious feats of urban planning" ever undertaken, Chinese officials are planning to combine nine cities in the prosperous Pearl River Delta region into a single, gigantic metropolis the size of Switzerland. The new megacity would be the largest in the world. How does China plan to pull off such a feat?

Just how big will this city be?
It will span 16,000 square miles — making it as large as New Jersey and Vermont combined. The population will be 42 million, roughly five times that of New York City. It will join together Guangzhou (12 million), Shenzhen (8.6 million), Dongguan (6.9 million) and six smaller cities that together account for about 10 percent of China's economy. The project is expected to take six years.

Why create a mega-city?
The thinking is that the cities' dwellers will benefit from beefed-up transportation links and infrastructure and that, ultimately, it will be cheaper to run the nine municipalities as one.

How will China roll them into one?
Bureaucrats will have to create an umbrella administration to control and coordinate nine robust city governments with sometimes competing priorities, says Brian Merchant in The Utopianist. The existing cities will have to be connected with high-speed rail — 3,100 miles of new rail forming 29 different lines — so citizens can easily get to health care facilities, jobs, and other resources anywhere in the region. The task of linking energy, water, transit, and sanitation facilities serving the existing cities will break down into 150 separate infrastructure projects.

Won't that cost a fortune?
Yes, the rail projects alone will set China back $196 billion. The rest of the infrastructure work will bring the price tag to $304 billion. But China considers the project a good investment: "It will help spread industry and jobs more evenly across the region and public services will also be distributed more fairly," says Ma Xiangming, the chief planner at the Guangdong Rural and Urban Planning Institute and a senior consultant on the project. "Residents will be able to choose where to get their services and will use the internet to find out which hospital, for example, is less busy."

Will the new city overshadow China's other metropolitan centers?
Not necessarily. For one thing, not everyone buys the argument that the Pearl River Delta will become like one giant city. The nine existing cities are just being connected by high-speed rail, says Chris Devonshire-Ellis at, so to call this a megacity "is a bit much."

What else is China planning?
Even if you view the as-yet-unnamed megacity as the largest metropolis in the world, it won't be for long. By the end of the decade, China plans to move even more people into its cities, creating even larger urban zones. In the north, the area around Beijing and Tianjin, two of China's most important cities, is being ringed with high-speed rail to link a super-urban area that could have a population as high as 260 million.

Sources: Telegraph, Time, The Utopianist, China-Briefing (2), Smart Planet, Infoplease