To me, the most important cause in the story comes when the man who is on his way to be hanged steps to one side to avoid stepping in the puddle. When he does this, the narrator realizes something very important. He realizes that this is a human being they are about to kill. Once he realizes this, the main tension of the story is set up -- the bad feeling the narrator has about the hangning.
The other cause would be the hanging itself. It causes all the things that the various men say afterwards. These are important because they show the various inhuman ways in which these men are reacting to the hanging.
The simple title, "A Hanging," lends a solemn, matter-of-fact tone and lack of emotion to the descriptions. The title itself implies no judgment, just as Orwell in this essay makes none explicit. However, one is left with little choice but to wonder at the shallowness of the people responsible for the hanging. The narrator sees clearly that the prisoner has a life "in full tide" (10) when the prisoner avoids a puddle. The narrator feels, as noted in paragraph 10, that somehow he is connected with all the men there, "together, seeing, hearing, feeling, understanding the same world." But the larger issue, to Orwell, involves the morality of capital punishment and the colonial rule that imposed it, as well as the small value placed on one Indian life.
What are causes in the story "A hanging" by George Orwell?