The Reserve Bank today announced another round of facility to inject liquidity of up to 12,000 crore rupees in the system, which is facing cash shortage due to the busy credit season and impending advance tax payments. Liquidity injection would be on December 15 through open market operations, under which RBI pumps in money by purchasing government securities held by banks.The central bank said this in a statement. The Government securities which the RBI will purchase this time are to mature in 2016, 2017, and 2022.This time the open market operations will be conducted on December 15, when corporates make third-quarterly advance payments that will suck out further money from the system.