What are the causes of revolt …

CAUSES:-

Economic causes:- collapse of traditional handicraft industries , increasing pressure on agriculture and land, high land revenue which was required to pay on a fixed date failing which lands were to be auctioned off .
Administrative causes:- corruption in the administration especially among petty officials, lower law courts and police.
Political causes:- policies of doctrine of lapse, subsidiary alliance and policy of Effective Control created discontentment among people. Annexation of Awadh proved that even the groveling loyalty can't satisfy British greed for territories.
Socio- Religious causes:- abolition of practices like sati, female infanticide, support to widow remarriage and female education were seen by many as an interference in their culture by the outsider.
Discontent among sepoys:- As per Laxmi Subramanian pay, pension and prospect were the main reason for discontent.
Influence of outside events:- British fought first Afghan war, Crimean war, Punjab wars and in all these wars the company had to incur huge losses. This had a great psychological repercussions.
Rumors :- Rumors such as mixing of bone dust with atta ( flour) and introduction of Enfield rifle , the catridges of which were made up of the fat of beef and pig , acted as a sparking point for the revolt.