Oil, copper and other commodities tumbled on Tuesday after China devalued the yuan, raising concerns that a persistently weaker currency will choke off demand in the world’s top commodities consumer. China’s central bank made what it called a “one-off depreciation” of nearly 2 percent in the yuan after a run of poor economic data, which sent the currency to a three-year low. The dollar gave up immediate gains made after the devaluation, which ordinarily would boost dollar-denominated assets, but such is the importance of China to commodities demand that investors overlooked any weakness in the U.S currency. “When you have the biggest customer for oil and commodities devaluing, then obviously you find your product coming under pressure and that is really how the day has panned out,” […]