Yesterday the People's Bank of China lowered the collateral requirement for medium-term loans:

The People's Bank of China (PBOC) said it would lower the collateral requirement for the medium-term lending facility (MLF) loan to increase the size of tradable bonds in the market. The move comes in the context of a record-long rally in China's sovereign bond markets that has prompted repeated central bank warnings and measures to put a floor under falling yields and prevent a market bubble.

Chinese state media are talking it up today, saying it'll alleviate the "asset famine" pressure on the bond market.

Info via Reuters

PBoC
PBoC