(Bloomberg) — China’s central bank governor said quantitative easing implemented by global peers can be damaging over the long term and vowed to keep policy normal for as long as possible.

Central banks should try their best to avoid asset purchases because in the long run they will “damage market functions, monetize fiscal deficits, harm central banks’ reputation, blur the boundary of monetary policy and create moral hazard,” People’s Bank of China’s Governor Yi Gang said in an article posted by the central bank Tuesday.

When central banks have to purchase assets, the programs should be in proportion to the size of the market’s trouble, Yi said. The interest rate in some economies have approached or even dipped below zero, he said.