It is just so hard to separate religion from culture as they overlap that much with each other. You simply cannot divorce one from the other. One must also take into consideration that India is not only a land of many cultures but religions also. For instance, it is the birthplace of both Hinduism and Buddhism which are two of the four major faiths of the world. Jainism and Sikhism were also birthed there.
Note that all four of these religions have a common thread running through them: They embrace the philosophies of karma and dharma. Whereas karma concerns itself with the law action and reaction, dharma has to do with the forces that govern the cosmos. Add to that the teachings of ahimsa or nonviolence, and you have in the making a peculiar but vibrant society. This brings to mind the great Mahatma Gandhi who not only liberated India by application of nonviolence, but the principle deeply inspired the Afro-American civil-rights leader Martin Luther King. There are also the prevalence of a fairly large population of Muslims, Christians and Zoroastrians coexisting side-by-side. These religions have all doted the Indian landscape and made for the fusion of an impressive array of distinct cultures, customs and heritages. India stands supremely as a non-secular nation where there is the absolute freedom of worship—a basic human right and privilege ever so much enshrined within its constitution and charter of rights.