A sunset view of Shanghai. [File photo/Xinhua]

The city of Shanghai, with its rapidly growing population, will boast the largest metropolitan area around the world within the next three to five years, the Chinese Academy of Social Sciences noted in a green paper on Nov 30. Shanghai's metropolitan population is to exceed that of Tokyo's biggest metropolitan circle.

The green paper pointed out that China's urbanization rate reached 56.1 percent in 2015, meaning that over half the country's population lives in urban areas. Shanghai stands out for its massive population, even among other metropolises in China and around the world.

Statistics show that the population density of Shanghai's downtown district is much higher than that of central Tokyo, though it is lower than that of Seoul and Beijing (within the city's 5th Ring Road). But it is worth noticing that the population density of Shanghai's outer area may already have surpassed that of other metropolitan areas. The population density of Shanghai's eight main districts was as high as 24,457 people per square kilometer in 2013, much higher than in the city centers of Shenzhen, Guangzhou and London.

The green paper indicated that, based on overall size, the gross population of metropolitan Shanghai now ranks second in the world, approaching that of Tokyo. Taking growth rate into consideration, the Shanghai metropolitan area will likely be the largest one anywhere in the world within the next five years.