I appreciate the answer of User 833. I would like to add a point or two. Being an Indian myself - I know that for Indians there is inbuilt lethargy to move towards a revolution. We as a people are content to change slowly not abruptly.
However historically there have been revolutions not in the sense of French Revolution or the October Revolution, but a revolution nevertheless. In June 1975, the Indian PM Mrs.Gandhi used the provisions of the Constitution to declare a state of Emergency wherein Individual Freedoms and Rights were abrogated - it was a dictatorship much like Stalin - any critic would face a midnight knock and be imprisoned without recourse to a court of law - yes they were not liquidated - that is the only difference.
The imposition of emergency was preceeded by a movement by the Gandhian Jai Prakash Narayan who felt the dreams of the Constituent Assembly was being ignored amidst growing nepotism and corruption. When the emergency was lifted Indian National Congress faced a new opponent in the polls declared. Prior to 1975 India was a a land of multiparty elections. This resulted in the Anti-Congress vote being split and the Congress emerging winner in election after election. During Emergency 14 or 15 different parties united to form a new party Janata Party. There was co-operation with the left parties too - Communist Party of India fought the elections unitedly and CPI's Indrajit Gupta became the Indian Home Minister. This unity wiped out Congress Party including Indira and her son Sanjay Gandhi from North India - the Congress Party is still to recover its sway over this region.
However the experiment was a failure and the Janata Party broke up before 1980 due to internal differences.
This can be really termed a revolution in India through the ballot not bullet.
Earlier in 1967 the Dravidian Parties in the state of Madras won a resounding victory over Congress Party and till date thee State of Madras (now Tamil Nadu) has not seen a Congress Government for more than 50 years.
This is just additional information to state that India does have its non-violent revolutions, but they are far and few. Many of them like Anna Hazare's movement collapse due to their inherent internal fault lines.