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).

Introduction:
Gandhiji started the Non-Cooperation Movement in 1920 as a response to the oppressive British rule in India. It was a significant step towards achieving independence and was characterized by passive resistance, civil disobedience, and nonviolent protests.

Reasons for Starting the Non-Cooperation Movement:
1. Rowlatt Act: One of the main triggers for the movement was the implementation of the Rowlatt Act in 1919. This act gave the British government extensive powers to suppress political dissent and curtail civil liberties.

2. Jallianwala Bagh Massacre: The brutal Jallianwala Bagh Massacre in April 1919 further fueled the anger and resentment towards the British rule. The indiscriminate firing on unarmed protesters by British troops led to widespread outrage.

3. Khilafat Movement: Another major factor that influenced Gandhiji's decision was the Khilafat Movement. This movement was initiated by Indian Muslims to protect the caliphate in Turkey, which was under threat from the British. Gandhiji saw the Khilafat Movement as an opportunity to unite Hindus and Muslims in the fight against their common oppressors.

Aims of the Non-Cooperation Movement:
1. Complete Independence: The primary aim of the movement was to achieve complete independence from British colonial rule. Gandhiji believed that non-cooperation and passive resistance could weaken the British administration and eventually lead to self-rule.

2. Boycott of British Goods: The movement aimed to boycott British goods, encouraging Indians to use locally made products instead. This was intended to weaken the economic power of the British and promote self-sufficiency.

3. Resignation from Government Jobs: As part of the movement, Indians were encouraged to resign from government jobs, which would disrupt the functioning of the British administration.

4. Non-Violent Protests: Gandhiji emphasized the use of nonviolent protests and civil disobedience as a means to challenge British authority. This approach aimed to create moral and political pressure on the British government.

Conclusion:
Gandhiji started the Non-Cooperation Movement in 1920 to challenge the oppressive British rule in India. The movement aimed to achieve complete independence through nonviolent protests, boycotts, and civil disobedience. It was a turning point in India's struggle for independence, as it mobilized millions of Indians and laid the foundation for future mass movements.