What was the immediate cause of the Uprising of 1857?

In 1856, the British authorities introduced the Enfield rifle which became the immediate cause of the Uprising of 1857. The loading process of the Enfield rifle involved bringing the cartridge to the mouth and biting off the top greased paper with the teeth. In January 1857, there was a rumour in the Bengal regiments that the greased cartridge had the fat of cow or pig. The sepoys were now convinced that the introduction of greased cartridges was a deliberate move to defile Hindu and Muslim religions as the cow is sacred to hindus and the pig is a taboo to Muslims. So, both the Hindus and the Muslim soldiers refused to use these cartridges and staged an uprising when they were forced to use them.