What were the factors of the Birsa movement?

The factors that led to the Birsa movement were as follows:

• Apathy of colonial authorities with respect to the rights of the tribal people to their land
• New laws that deprived tribal people of their land
• Arbitrary exploitation and oppression of the tribal people by the British government

 For further reading check the following articles:

• Peasant Movement and Tribal Uprisings
• Popular Uprisings in 18th and 19th Centuries