Zhuhai, located at the southern tip of the Pearl River Delta of south China's Guangdong Province, tops the list of China's most sustainable cities. It is followed by Shenzhen, Hangzhou, Xiamen, Guangzhou, Dalian, Fuzhou, Beijing, Changsha and Yantai, according to a report.

The Urban China Initiative (UCI) launched the 2013 Urban Sustainability Index (USI) Report on Wednesday. According to 23 metrics that cover areas of the economy, society, resources and environment, 185 cities of varying sizes and at different stages of development are ranked by their level of sustainability from 2005 to 2011.

"USI serves more than a tool. Based on the scores in each category, Chinese cities can find out their strengths and weaknesses and strategize accordingly. They can also evaluate the effectiveness of their policies and identify models of urban development in and outside China." Jonathan Woetzel, Co-Chair of UCI and Director of McKinsey & Company, said at the report launch.

Key findings of the 2013 Urban Sustainability Index (USI) Report include:

The level of sustainability has improved in most Chinese cities.

Most Chinese cities are gradually improving their level of sustainability, especially in the social and environmental aspects. The progress reflects healthy economic growth as well as a continued emphasis on bettering the society and the environment.

Top 10 cities leading in sustainability are mostly located in coastal or eastern regions.

According to the data of 2011, the top scorers in sustainability were Zhuhai, Shenzhen, Hangzhou, Xiamen, Guangzhou, Dalian, Fuzhou, Beijing, Changsha and Yantai.

Situated in geographic locations favorable for trade and investment, eastern cities are the early beneficiaries of China's economic liberalization policies. In the report, eastern cities have higher scores in overall sustainability, followed by cities in central and western China.

Although the sustainability level of Chinese cities correlates positively with economic strength, per capita GDP does not indicate a city's level of sustainability.

The top 10 cities constitute around 1 percent of China's urban population and 16 percent of its urban GDP. Except for mega-cities such as Shenzhen, Guangzhou and Beijing, most of them are medium-sized, with a population of 1.5-6.5 million. The cities' population density is 7,000- 10,000 people per square kilometer, with the exception of Beijing, which has around 14,000 people per square kilometer. But the top scorers are no leading cities in per capita GDP. Their per capita GDP is 9,000-100,000 yuan, while the highest per capita GDP can reach 200,000 yuan for Chinese cities.

In the long run, the sustainability level of Chinese cities correlates positively with economic strength. Positive correlations are also found to some extent with the size and density of population, density, FDI and migration.

Major gaps between Chinese cities and their international benchmarks exist in the social, economic, and environmental aspects.

Although China is improving in its sustainability, most Chinese cities still have a long way to go in narrowing their gaps with global benchmark cities. Major gaps between Chinese cities and their international benchmarks exist in the social, economic, and environmental aspects, such as urban employment, per capita number of doctors, industrial air pollution, sewage treatment, etc.

The Urban Sustainability Index (USI) is jointly developed by the Urban China Initiative (UCI) and the McKinsey Global Institute (MGI). The first USI report was published in 2011.