If happiness is a measure of economic success, as China's 12th five-year plan affirms, we could be in trouble. Hongkongers, while rich, are among the least happy in the nation, according to an annual study by the Chinese Academy of Social Sciences - the central government's top think tank. The city was named the most competitive in China for the sixth year in a row, but it dropped 73 places to 271st out of 294 cities on an index measuring people's happiness. The annual survey covers the mainland, Hong Kong, Macau and Taiwan. It assesses cities' happiness by measuring residents' confidence in their future, their living conditions, environment and hygiene, employment and social welfare. Shijiazhuang, capital of Hebei province and the base for the Sanlu Group - blamed for the melamine-adulterated milk scandal in 2008 that saw 300,000 babies fall ill and several die - ranked first for happiness. Beijing is also in the top 10, together with a number of less well-known medium-sized cities. Surprisingly, scenic Suzhou and Hangzhou - known in Chinese culture as 'paradise on earth' are even more unhappy than Hong Kong - ranked 276th and 289th, respectively. Popular holiday destination Guilin ranks 291st. The report notes Hong Kong is facing a widening gap between the rich and poor that could undermine social stability. Dr Li Pang-kwong, director of the public governance programme at Lingnan University, said: 'Hong Kong's low ranking in the happiness index is in line with the growing discontent over the unequal distribution of wealth.' Chen Wenling, a central government official from Shijiazhuang who announced the findings, admitted many people may not agree with the index. 'Every time I return to Shijiazhuang, I hear complaints,' she said at a press conference in Beijing yesterday. The 12th five-year plan seeks to shift economic strategy from one focused on rising output to one centred on people's happiness.