What are the basis of communalism?

Communalism is based on the idea that religion is the principal basis of social community. It involves thinking along the following lines :
(i) The followers of a particular religion must belong to one community with the same fundamental interests.
(ii) It also follows that people who follow different religions cannot belong to the same community.
(iii) If the followers of different religions have some commonalities these are superficial and immaterial. Their interests are bound to be different and involve a conflict.
(iv) In its extreme form communalism leads to the belief that people belonging to different religions cannot live as equal citizens within one nation.