A notable increase does not imply a large amount of violence. And personally I doubt that India had less sectarian violence in the past; it was just covered less dramatically.
For quite a lot of the sectarian violence, I blame the government and the political parties for having policies that favour some castes over others, and for being soft on sectarian violence. Moreover we, in the middle class, who lead lives far away from politics, are largely isolated from these shenanigans.