The reasons of 1857 freedom struggle : 

Economic :

1. New revenue system introduced by the British to increase their income and impoverish the peasants. 

2. The farmers had to either sell or mortgage their land to pay tax in cash. 

3. In order to sell British goods in India and earn profit they imposed heavy taxes on local industries. 

4. Many artisans lost their livelihood as 8 handicraft and textile industries ruined.

Political :

1. The British captured many g states after winning the Battle of Plassey in 1757. 

2. Lord Dalhousie annexed many princely states on various reasons.

3. He dethroned the Nawab of Ayodhya and annexed Ayodhya under the pretext of maladministration ? 

4. He annexed princely states of Jhansi, Nagpur and Satara through Doctrine of Lapse. 

5. Due to these policies of Lord Dalhousie the Indians had no trust in the British.

All these factors created discontent among artisans, princes and other classes f which ultimately led to the freedom struggle of 1857.