About 104 million people in India are members of Scheduled Tribes, which accounts for 8.6 % of India's population (according to the 2011 census). In the census of India from 1871 to 1941, tribals have been counted in different religions from other religions,1871(other religion), 1881(Aboriginal) ,1891(forest tribe), 1901(animist),1911(Animist), 1921(Primitive), 1931(Tribal religion), 1941(tribes), However, since the census of 1951, the tribal population has been stopped separately. Many Indians belonging to these populations adhere to traditional Indian tribal religions, often syncretised with one or more of the major religious traditions of Hinduism, Buddhism, Islam and/or Christianity and often under ongoing pressure of cultural assimilation.
The tribal people observe their festivals, which have no direct conflict with any religion, and they conduct marriage among them according to their tribal custom. They have their own way of life to maintain all privileges in matters connected with marriage and succession, according to their customary tribal faith.
In keeping with the nature of Indian religion generally, these particular religions often involve traditions of ancestor worship or worship of spirits of natural features. Tribal beliefs persist as folk religion even among those converted to a major religion.
The largest and best-known tribal religion of India is that of the Santhal of Orissa. In 1991, there were some 24,000 Indians belonging to the Santhal community who identified explicitly as adherents of the Santhal traditional religion in the Indian census, as opposed to 300,000 who identified as Christians. Among the Munda people and Oraons of Bihar, about 25 % of the population are Christian. Among the Kharia people of Bihar (population about 130,000), about 60 % are Christians, but all are heavily influenced by Folk Hinduism. Tribal groups in the Himalayas were similarly affected by both Hinduism and Buddhism in the late 20th century. The small hunting-and-gathering groups in the union territory of the Andaman and Nicobar Islands have also been under severe pressure of cultural assimilation.