Christianism, Islam, Buddhism, Jainism, Sikhism, Vaishnavism are not religions, they are organisations. It is organised by some one(the personal god) and preached by them. For eg, the personal god of the above said religions are- christian-jesus christ islam-muhammed jain-mahavir buddhism-buddha vaishnavism-krishna sikhism-guru nanak
from this we can say that they are fans of those organisers. Like in the modern day world, cine actor/politicians, etc has followers. So, we can say congress is too a religion. Is it not?
But to me, look after the history of your forefathers(HARAPPA CULTURE). The coming of aryans disrupted Harappans. Aryans comprise UP,Bihar, North WB, HP,Punjab, Northern Rajasthan, Northern MP and NOT THE CENTRAL AND SOUTH INDIA. More to know...wait