The Shanghai Composite index fell 12 points, or 0.4%, to 2979 on Wednesday, amid political tensions after the country’s foreign ministry said it resolutely opposed an act passed by the US congress voicing support for protesters in Hong Kong, describing the move as interfering in China’s internal affairs. Also, China’s central bank injected $28bn of liquidity into the financial system via its medium-term lending facility, suggesting weakness in the upcoming macroeconomic data.