China's central bank ?said ?on Tuesday that it ?will raise the amount of foreign currency ?that financial institutions must hold as reserves, a move aimed at tightening ?dollar liquidity conditions and ?slowing the pace of recent yuan gains. The People's Bank ?of China (PBOC) ?said it would raise the foreign exchange reserve requirement ?ratio (RRR) by 2 percentage points to 6% from 4%, effective on November 15, according to an online statement.