Potti Sriramulu
The man who changed India's map.
Before independence (and partition), most of India's political leaders agreed that India should be divided into states on the basis of language.
However, with partition, this was put on hold by Nehru, in fear of further dividing the country on lines of language, after it had already been divided on the basis of religion.
Potti Sriramulu was a Gandhian who began a fast-unto-death in protest of this decision which meant that Andhra Pradesh would not be created for Telugu speakers, from the province of Madras. The government of India ignored this fast, until 58 days later, Sriramulu died. Hell broke loose after that. Government offices were vandalized, trains wrecked. Several protestors were killed in police firings.
The government had to give in to the ask of creating Andhra Pradesh from the Telugu speaking districts of Madras. This gave strength to similar arguments of states based on language to other parts of India like Punjab, Maharashtra etc.