China’s central bank joined its European counterpart in boosting liquidity to address weakening growth, underscoring a divergence in direction among the world’s biggest economies as the U.S. The People’s Bank of China is injecting 500 billion yuan ($81 billion) into the nation’s largest banks, according to a government official familiar with the matter, signaling the deepest concern yet with an economic slowdown. China’s credit expansion builds on targeted measures to shore up growth while stopping short of broad-based stimulus seen in the U.S.