Noncooperation movement, unsuccessful attempt in 1920–22, organized by Mohandas (Mahatma) Gandhi, to induce the British government of India to grant self-government, or swaraj, to India. It was one of Gandhi’s first organized acts of large-scale civil disobedience (satyagraha). The movement arose from the widespread outcry in India over the massacre at Amritsar in April 1919, when the British-led troops killed several hundred Indians. That anger was later compounded by indignation at the government’s alleged failure to take adequate action against those responsible, notably Gen. Reginald Edward Harry Dyer, who had commanded the troops involved in the massacre. Gandhi strengthened the movement by supporting (on nonviolent terms) the contemporaneous Muslim campaign against the dismemberment of the Ottoman Empire after World War I. The movement was to be nonviolent and to consist of Indians resigning their titles; boycotting government educational institutions, the courts, government service, foreign goods, and elections; and, eventually, refusing to pay taxes. Noncooperation was agreed to by the Indian National Congress at Calcutta (now Kolkata) in September 1920 and launched that December. In 1921 the government, confronted with a united Indian front for the first time, was visibly shaken, but a revolt by the Muslim Moplahs of Kerala (southwestern India) in August 1921 and a number of violent outbreaks alarmed moderate opinion. 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.