In India, everything is related to religion. Right from our daily mundane activities to sophisticated things like ceremonies. And our culture too. Culture and religion, i guess are two inseparable entities. Whatever defines 'culture'? But we are kinda defined by it, aren't we?
When i first heard that a person does not belong to any religion at all, i was surprised. How could they? Coming from a land where religion plays an 'essential' role in one's existence, this was unthinkable. It's just that the parents did not baptize them as kids. And hence they are not affiliated to any religion. But that does not make them very different from us. They do not celebrate Christian festivals. Does that create a lot of difference between those who are affiliated with a religion and those who are not?
Perhaps, culture should be associated with ethnicity, than religion. In my opinion, it makes more sense that way. In my country, i think it's a mixture of all the three.