China's aluminium output fell 8.2 percent in July from a record high a month earlier, data showed on Monday, as capacity cuts that have sent prices to multi-year highs start to take their toll on the country's output.

The world's top aluminium producer churned out 2.69 million tonnes of the metal last month, from 2.93 million tonnes in June, according to the National Bureau of Statistics (NBS).

 The decrease in China's aluminium output follows significant supply-side reform in the sector that sent Shanghai aluminium futures prices to around five-year highs last week.

The eastern province of Shandong, China's biggest aluminium-producing region, ordered a bigger-than-expected 3.2 million tonnes of "illegal" capacity to be closed by the end of July.Mean while Henan provcine is willing to cut its aluminum production in winter.

The U.S. Department of Commerce last week made a preliminary decision to slap antidumping duties ranging from 16.56 percent to 80.97 percent on imports of aluninium foil from China .

Export data released last week showed China's aluminium shipments overseas were down 4.3 percent month-on-month at 440,000 tonnes in July.