Among the 68 million citizens of India who are members of tribal groups, the religious concepts, terminologies, and practices are as varied as the hundreds of tribes, but members of these groups have one thing in common: they are under constant pressure from the major organized religions. One of the most studied tribal religions is that of the Santhal of Orissa, Bihar, and West Bengal, one of the largest tribes in India, having a population estimated at 4.2 million. According to the 1991 census, however, only 23,645 people listed Santal as their religious belief.