BEIJING — China's central bank announced on Tuesday it had pumped more than 590.3 billion yuan ($85.6 billion) into the market via multiple tools in April.

The People's Bank of China (PBOC) said it injected 495.5 billion yuan via the medium-term lending facility (MLF) to keep liquidity basically stable.

The MLF operation includes 128 billion yuan that will mature in six months and 367.5 billion yuan that will mature in one year, bringing the total outstanding MLF loans to 4.1 trillion yuan at the end of April.

The interest rates stood at 3.05 percent for the six-month MLF and 3.2 percent for the one-year MLF.

The MLF tool was first introduced in 2014 to help commercial and policy banks maintain liquidity by allowing them to borrow from the central bank by using securities as collateral.

The central bank has increasingly relied on open-market operations for liquidity, rather than cuts in interest rates or reserve requirement ratios to maintain prudent monetary policy.

In addition to the MLF, standing lending facilities (SLF) were also used last month.

A total of 10.89 billion yuan was granted in April to financial institutions via SLF to meet provisional liquidity demand.

In addition, the PBOC injected 83.9 billion yuan through pledged supplementary lending (PSL) to China Development Bank, Agricultural Bank of China and the Export-Import Bank of China.