What was the "dirty work of empire" in "Shooting an Elephant"?

"The dirty work of empire" in "Shooting an Elephant" is the violence used by imperialists to maintain control over colonized peoples. Orwell, who uses this phrase, describes it this way:

the wretched prisoners huddling in the stinking cages of the lock-ups, the grey, cowed faces of the long-term convicts, the scarred buttocks of the men who had been Bogged with bamboos...

As an imperial policeman, Orwell's narrator says that he was in a position to see this "dirty work" firsthand. He has no illusions about empire, indeed he says that he hates being part of such a corrupt institution. At the same time, he is conscious that the Burmese people hate him, and even though he doesn't really blame them, he hates them too. Really, the incident that forms the basis of this short story--the shooting of the elephant that has briefly run amok in the bazaar, is itself an example of the "dirty work of empire." When the elephant kills a man, the people demand, indeed expect, that Orwell will reciprocate by killing the elephant. That he does not want to do so, but does anyway simply to avoid "looking a fool," simply underscores the "dirty" and debasing nature of the entire imperial project. To maintain legitimacy in the eyes of the Burmese people, he must carry out a deed that is contrary to his own morality. He must become the violent thug that the Burmese believe him to be.