Why does Gandhi call off the campaign of noncooperation

After an angry mob murdered police officers in the village of Chauri Chaura (now in Uttar Pradesh state) in February 1922, Gandhi himself called off the movement; the next month he was arrested without incident. The movement marked the transition of Indian nationalism from a middle-class to a mass basis

Explanation: (thank me later :>)

the use of email to replace slower surface mail.