Communalism is a situation where different religious groups try to establish their supremacy over the other religion groups .

Communalism is a philosophy which believes in society being divided into a number of religious communities that are different from each other and opposed to each other. In this kind of society, each community think itself as superior to others.
Communalism is a situation when a particular community tries to promote its own interest at the cost of other communities.Communal politics is based on the idea that religion is the principal basis of social community. Communalism involves thinking along the following lines:• The followers of a particular religion must belong to one community.• Their fundamental interests should be the same. Any difference that they may have is irrelevant or trivial for community life.• Communalism also follows that people who follow different religions cannot belong to the same social community. 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.• Sometimes, communalism leads to the belief that people belonging to different religions cannot live as equal citizens within one nation. Either one of them has to dominate the rest, or they have to form different nations.

It is a negative thinking in which one caste person starts thinking that my caste is superior than others . It can cause civil war like conditions

When one religion is pitted against other by the political class, this is known as communalism..
When people of one religion get more support from govt. Is called communalism