White sugar tumbled on Wednesday in London on concern that increasing output in China and Brazil will add to a global surplus.

White sugar for August delivery dropped 1.9 percent or $7 to $357 a ton on the Liffe exchange.

Sugar prices have increased by 7.5 percent this month.

Sugar futures for July delivery declined by 1.4 percent or 0.18 cent to 12.77 cents a pound on ICE Futures U.S., formerly the New York Board of Trade.

The Sugar and Ethanol Industry Association forecasted production in Brazil's center south region which accounts for more than 80 percent of the nation's sugar output, to increase by 9.2 percent to 28.6 million metric tons from a record cane harvest of 498 million tons.

China's sugar output was forecasted to reach 14 million tons this year, 8.5 percent higher than last season.

The International Sugar Organization in London forecasted global sugar surplus to reach 9.3 million tons in the year through Sept. 30.