No doubt Islam is a GREAT religion, but the MAJORITY of muslims (including those in India) are extremists. Clearly this religion and its followers need some reforms. And these reforms should come from their own communities.
For example, some ancient (17th century) practices that must be abandoned : 1) butchering goats at home. 2) subjugation of females. 3) hypocritical practices like wearing burqa. 4) being misled by extremist community leaders. because these practices are simply not compatible with the modern world.
Unless muslims accept a little bit of change with the modern world, this menace of terrorism can't be eradicated. The first step (for the muslims) is to accept the fact that the majority of muslims today have extreme views, then the second step would be to start accepting modernism.