The answer is: He began the trend of using nonviolence to protest unfair treatment of groups of people.
Mohandas Gandhi was an Indian activist who evoked a spirit of national unity between the peoples of India in seeking to liberate them from British colonial rule during the 20th century. In his advocacy for liberation, he is well-known for having implemented non-violent resistance to injustice and inequality and, even though he was not the first person to develop this form of resistance, he is, indeed, the most renowned and successful historical figure who made use of this form of civil resistance in the 20th century.