Dear Student,
Immediate cause of the revolt 1857 was the introduction of enfield rifles in the army which was rumoured to be greased with the meat of beef or pork. Sepoys had to bite the cartridge open to release the powder. This angered the hindus and the muslims in the army as it hurt their religious sentiments.For Hindus cow aws considered to be sacred and for Musims pig is considered to be dirty.
Mangal pandey revolted by firing at the british officer and started the revolt.