In March 1920, he revealed his proposal for the Non-Cooperation Movement. This was a direct response to the British crackdown on Punjab, particularly the Jallianwala Bagh massacre, as well as the Khilafat question. Even though the Congress party did not formally adopt the resolution until September 1920, the Non-Cooperation Movement officially began in December 1920. However, Gandhi had begun to mobilize the movement as early as 1920.