Connection to The Waste Land 
The poem begins by the reverie of the protagonist: people thought April is the sweet month of rebirth, but it’s actually not because it tortures the inhabitants of the waste land with unstoppable recollections, so it’s the cruelest. April stirs new life in the world of nature. This stirring of life and return of fertility is painful and repugnant (offensive) to the dead because it reminds them of the need for renewing their own lives. This
kind of creates a disturbance of n the dead. As for the people, those who do not wish a new life think April is the cruelest month because in another sense it suggests April brings changes or resurrections to those who do not wish for them it.