In the aftermath of the crisis it has become, at times, more difficult for central banks to achieve the slow increase of price levels that they aim for. This is also true in the euro area where, thanks mainly to falling oil prices, inflation is currently around zero.
That would not be a serious problem if we saw low inflation only for one or two months, but it becomes worrisome if there is a risk of too low inflation for too long. In that scenario, it can start to affect people’s expectations of future inflation, which then makes low inflation self-fulfilling.