In 1921,during which one of the following tours, Gandhiji shaved his head and began wearing loincloth in order to identity with the poor?

On 22nd September 1921, Gandhi made a momentous decision to change his attire. From the elaborate Gujarati attire, he decided on a simple dhoti and shawl. This epoch-making decision was taken by Gandhiji in Madurai after he decided that he has to work for and with the with the poor people of India and how can he identify with them if he wears different clothes from them.