Hello,

Ancient India was United without such communal feelings

There was acceptance for each other's culture and Tradition

Example: Ashoka followed religious tolerance and focussed on Dharma

It was practised in several kingdoms of India

There was Peace and harmony

But , Aurangzeb was least tolerant for other religious practices

The root cause of communalism was partition of Bengal in 1905

It was the result of modern politics emergence

Gandhi and others had a strong resistance through  communal award represented by British government who appeased various communities

Muslims and other communities are also appeased by British government for their political needs

Hope it helps