Comment by ethbr1

Same approach China is taking -- harsh penalties + heavy press broadcasting in the most egregious instances uncovered, with an emphasis on consequences for the high ranking folks involved.

You don't want to try to catch everyone, as then people do worse things trying to cover their tracks, but you do want to establish a credible fear of consequences that will shift the default societal balance point between {do corruption} and {don't}.

And it may take a generation, but it is possible.