If the inflation rate in specific member states of EMU exceeds the stability standard of the ECB, such overshooting has to be offset by correspondingly lower inflation rates in the other countries.
The cost of deflation protection had also gone up by 185 basis points between 2 December 2014 and 9 January 2015, showing that investors saw a material risk that inflation could fall further and real interest rates could rise more. In this situation, it was absolutely essential that we re-anchored inflation expectations and warded off this potential tightening.