Apparently Pope Francis has little patience for dirty politicians, and in a blistering address compared public corruption to "bad breath" as reported by Darren Boyle for the Daily Mail:
'The scandalous accumulation of global wealth is possible because of the connivance of those with strong powers who are responsible for public affairs. The corrupt one does not perceive his own corruption. It is a little like what happens with bad breath: someone who has it hardly ever realises it; other people notice and have to tell him. Corruption is an evil greater than sin. More than forgiveness, this evil needs to be cured."
No word on how Pope Francis developed the comparison of stinkin' politicians with bad breath but the best speculation is that Barack Obama blasted the good pontiff with a foul stench each time the American President opened his piehole during their March meeting, and a metaphor was born. It's as if Obama's orifices have been swapped, and he's actually farting and spewing diarrhea when he's speaking.
Further reading that may be of interest: