What's the religion of most people who live in India?

The majority of India's citizens are Hindus, although with
more than a billion people, India is a plural society with many, many religions. 
According to the World Factbook, about four in five people in India are Hindus, while
just over 13% are Muslims and roughly 2% Christians and 2%
Sikhs.

Just as in the US, however, much of the nation is
secular, meaning they claim Hinduism as a religion, but do not follow it strictly. 
There is also considerable tension between Hindus and Muslims and Hindus and Sikhs, and
that has led to rebel movements, violent riots and even civil
war.

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labeled "People")