(a) Colonisation affected people's freedom, and nationalist sentiments surged during the process of struggle against imperial domination. The sense of oppression and exploitation became a common bond for people from different walks of life, and this resulted in the growth of nationalist ideals. Thus, growth of nationalism in the colonies is linked to anti-colonial movements.
(b) During the First World War, the British army conducted forced recruitment from rural areas in India. To finance the defence expenditure, high custom duties and income taxes were imposed. Also, during 1918-19 and 1920-21, crops failed in many parts of India, thereby resulting in acute food shortages. All this caused extensive anger and opposition against the British colonial rule, and the national movement of India headed towards a stronger, more definitive direction.
(c) The Rowlatt Act was passed hurriedly through the Imperial Legislative Council despite opposition from Indian members. It gave the government autocratic powers to repress political activities besides allowing it to detain political prisoners without a trial, for two years. The Indian were outraged by this act as it was clearly undemocratic and oppressive, and hurt national sentiments and dignity.
(d) Gandhi ji decided to withdraw the Non-Cooperation Movement due to various incidents of violence perpetrated by the masses, especially the Chauri Chaura incident in 1922 where the people clashed with the police, setting a police-station on fire. Gandhi ji felt that the people were not yet ready for a mass struggle, and that satyagrahis needed to be properly trained for non-violent demonstrations.