Explanation: The Calcutta Congress session of 1920 was a pivotal event in the Indian National Congress's history and the broader context of the Indian independence movement. This session, held in September 1920, was significant for several reasons:
1. **Historical Context**: The Indian National Congress, founded in 1885, had been advocating for greater autonomy and rights for Indians under British rule. By 1920, the political landscape had changed significantly, with the rise of more radical leaders like Mohandas Gandhi, who advocated for a more assertive approach to achieving Indian independence.
2. **Non-Cooperation Movement**: The most significant outcome of the Calcutta Congress session was the launch of the Non-Cooperation Movement. This movement was a strategy to achieve Indian independence through non-violent means, including the boycott of British goods, institutions, and titles. Gandhi's leadership was crucial in mobilizing the masses and providing a clear direction for the movement.
3. **Shift in Strategy**: Prior to the Calcutta Congress session, the Indian National Congress had largely pursued a policy of cooperation with the British, seeking reforms and concessions through dialogue. The session marked a significant shift towards a more confrontational approach, with the Non-Cooperation Movement being a direct challenge to British authority.
4. **Significance of the Date**: The session was held in September 1920, which is the correct date among the given options. This date is important as it aligns with the broader timeline of the Indian independence movement, where the Non-Cooperation Movement played a crucial role in galvanizing public support and setting the stage for future movements.
5. **Impact on Indian Politics**: The Non-Cooperation Movement, launched at the Calcutta Congress session, had a profound impact on Indian politics. It brought together a wide range of social and political groups under a common cause, fostering a sense of national unity and purpose. The movement also laid the groundwork for future movements and strategies, including the Civil Disobedience Movement and the Quit India Movement.
In conclusion, the Calcutta Congress session of 1920 was a turning point in the Indian independence movement, marking the beginning of a more assertive and non-cooperative approach towards British rule. The session's significance lies in its role in launching the Non-Cooperation Movement, which was a critical phase in the struggle for Indian independence. Understanding the historical context and the specific date of the session is essential for comprehending the broader narrative of the Indian independence movement.