China's primary aluminium output in May fell slightly versus April, official data showed on Wednesday, as restrictions on power consumption in the smelting hub of Yunnan forced some production cuts.

The world's top producer of the metal churned out 3.32 million tonnes in May, the National Bureau of Statistics said. That was down 0.8% from April's record high of 3.346 million tonnes but up 11.3% year on year.