China's central bank on Thursday announced new rules to make cross-border data flow in the financial sector easier while ensuring security.A guideline has been jointly released by six departments to promote high-level openness in finance, focusing on personal information and key data sent overseas, according to the People's Bank of China.The rules clarify how financial data can move across borders and exempt certain business activities from data security checks, the bank said, adding that financial institutions must still use necessary safety measures to protect data.