The Non-Cooperation Movement (NCM) was the first national movement that Gandhi launched in 1920.
CAUSES –

1)World War I: The good intentions of the war time were shattered when the British government back out on its promise to consider the needs of the people in return for India’s support in the war.

2)Montagu-Chelmsford Reforms: The reforms-introduced by the British government through montagu -Chelmsford in the form of the government of India Act 1919 failed to meet India’s need for self-government and the government’s desired need for accountability.

3)Rowlatt Act: Passed in 1919, this law allowed the arrest and imprisonment of NativeAmericans without trial.

4)Jallianwala Bagh Massacre: The Jallianwala Bagh Massacre in Amritsar, in which British troops opened fire on a peaceful gathering of Indians, killing hundreds, shocked and enraged the Indian population.

5)Khilafat Movement: The Khilafat Movement was a parallel movement initiated by Indian Muslims to protest against the dismantling of the Ottoman Caliphate by the British after the First World War. Gandhi supported the Khilafat cause and advocated for non-cooperation.

9th of January is Pravasi Bhartiya Diwas. It is a day observed to celebrate the contribution of the overseas Indian community in development of the nation.It is also the day Mahatma Gandhi returned from South Africa to India in 1915.