Brahmajala Sutta (Theravada)
In the second part, the Buddha explains the major beliefs of ascetics in India. He begins by saying, ""Monks, there are other things which are very deep (profound), very hard to understand, very difficult to perceive, so holy and sacred, unreached by means of mind, so subtle, that they are only to be understood and experienced by the wise. These things were perceived clearly, seen clearly and were discarded by the Tathagata, and by this act based on the truth that people praise and revered Tathagatha. What are those things?""
Irreligion in India
According to the 2005 Global Index of Religion and Atheism report from WIN-Gallup, 87% of Indians were religious and 4% called themselves atheists. According to the 2012 report by the same organisation, 81% of Indians were religious, 13% were not religious, 3% were convinced atheists and 3% were unsure or did not respond.