Explanation:

December 1920 at the Nagpur session of the Indian National Congress—
The programme of non-cooperation was endorsed;
An important change was made in Congress creed: now, instead of having the attainment of self-government through constitutional means as its goal, the Congress decided to have the attainment of swaraj through peaceful and legitimate means, thus committing itself to an extraconstitutional mass struggle;
Some important organizational changes were made: a Congress Working Committee (CWC) of 15 members was set up to lead the Congress from now onwards; Provincial Congress Committees on linguistic basis were organized; ward committees was organized; and entry fee was reduced to four arenas;
Gandhi declared that if the non-cooperation programme was implemented completely, swaraj would be ushered in within a year.
Do you know?
•Many groups of revolutionary terrorists, especially those from Bengal, also pledged support to the Congress programme. At this stage, some leaders like Mohammad Ali Jinnah, Annie Besant, G.S. Kharpade and B.C. Pal left the Congress as they believed in a constitutional and lawful struggle, while some others like Surendranath Banerjee founded the Indian National Liberal Federation and played a minor role in national politics hence forward.
THINK!
•Chauri Chaura Incident.