I assume what you want to know is why George Orwell wrote "Shooting an Elephant." While there is no particular occasion which prompted this essay, Orwell writes this autobiographical work as a kind of continuation or addendum to his work Burmese Days. Orwell's views on Imperialism were quite well known, so this essay would not have been a surprising thing for him to write.
Orwell's essay is set in Burma (formerly Myanmar) at a time (1931) when Burma is under the control of the British. He writes about his time working for the Indian Civil Service as a member of the Imperial Police. It was a job he despised, as he sympathized with the Indians:
Theoretically – and secretly, of course – I was all for the Burmese and all against their oppressors, the British.
Orwell recounts an experience in which he is forced to shoot an elephant because it is what was expected of him. The elephant has gone wild and is doing damage in the city; something must be done. Though Orwell does not want to shoot the creature, the natives are so hostile that he feels compelled to shoot the elephant just to save face and maintain his authority. The entire incident is a portrait of the distrust and resentment which both the natives (the Indians) and the authorities (their British oppressors, according to the people and, it seems, to Orwell) experience on a daily basis.
This essay created a flurry of controversy about whether Orwell was writing an apology for British authoritarian rule or a condemnation of it. Both sides say he did not go far enough neither his apology nor in his condemnation. This fact suggests that perhaps Orwell just wanted people to experience his dilemma as an unwilling oppressor.
Here was I, the white man with his gun, standing in front of the unarmed native crowd – seemingly the leading actor of the piece; but in reality I was only an absurd puppet pushed to and fro by the will of those yellow faces behind.
In either case, it is clear that Orwell believed both parties were trapped in their roles.