China will overtake the US to become the world's largest economy by 2020, which, in turn, will be overtaken by India in 2050. Going only by GDP growth, nine of the top 10 cities in the world are in China. The top 20 are all in China or India, the study said.

India is likely to emerge the world's largest economy by 2050, overtaking China, a study says. The Wealth Report 2012 by Knight Frank and Citi Private Bank released in Hyderabad on Wednesday said China will overtake the US to become the world's largest economy by 2020, which, in turn, will be overtaken by India in 2050. Going only by GDP growth, nine of the top 10 cities in the world are in China. The top 20 are all in China or India, the study said, adding "we believe the cities to watch in 2050 are the 400 emerging market 'middleweights' fast growing cities with populations between 200,000 and 10 million." This dynamic group includes many cities including Nagpur and Surat in India, besides Linyi, Kelamayi and Guiyang in China and Concepcion and Belem in Latin America.