China’s poisoned air has risen up the political agenda after reports that the Government forced the World Bank to censor a study for fear that one of its findings – that 750,000 people die of pollution-related illness each year – might stoke social unrest.

The World Bank study, produced in co-operation with Chinese government ministries, found about 750,000 people die prematurely in China each year, mainly from air pollution in large cities.

China’s State Environment Protection Agency (Sepa) and health ministry asked the World Bank to cut the calculations of premature deaths from the report when a draft was finished last year, according to Bank advisers and Chinese officials.

Advisers to the research team said ministries told them this information, including a detailed map showing which parts of the country suffered the most deaths, was too sensitive.

“The World Bank was told that it could not publish this information. It was too sensitive and could cause social unrest,” one adviser to the study told the Financial Times.

Sixteen of the world’s 20 most polluted cities are in China.