It is impossible to know India without understanding its religious beliefs and practices, which have a large impact on the personal lives of most Indians and influence public life on a daily basis. Indian religions have deep historical roots that are recollected by contemporary Indians. The ancient culture of South Asia, going back at least 4,500 years, has come down to India primarily in the form of religious texts. The artistic heritage, as well as intellectual and philosophical contributions, has always owed much to religious thought and symbolism.
Contacts between India and other cultures have led to the spread of Indian religions throughout the world, resulting in the extensive influence of Indian thought and practice on Southeast and East Asia in ancient times and, more recently, in the diffusion of Indian religions to Europe and North America. Within India, on a day-to-day basis, the vast majority of people engage in ritual actions that are motivated by religious systems that owe much to the past but are continuously evolving. Religion, then, is one of the most important facets of Indian history and contemporary life.
A number of world religions originated in India, and others that started elsewhere found fertile ground for growth there.
Devotees of Hinduism, a varied grouping of philosophical and devotional traditions, officially numbered 687.6 million people, or 82 percent of the population in the 1991 census.
Buddhism and Jainism, ancient monastic traditions, have had a major influence on Indian art, philosophy, and society and remain important minority religions in the late twentieth century. Buddhists represented 0.8 percent of the total population while Jains represented 0.4 percent in 1991.
Islam spread from the West throughout South Asia, from the early eighth century, to become the largest minority religion in India. In fact, with 101.5 million Muslims (12.1 percent of the population), India has at least the fourth largest Muslim population in the world (after Indonesia with 174.3 million, Pakistan with 124 million, and Bangladesh with 103 million; some analysts put the number of Indian Muslims even higher — 128 million in 1994, which would give India the second largest Muslim population in the world).
Sikhism, which started in Punjab in the sixteenth century, has spread throughout India and the world since the mid-nineteenth century. With nearly 16.3 million adherents, Sikhs represent 1.9 percent of India's population.
Christianity, represented by almost all denominations, traces its history in India back to the time of the apostles and counted 19.6 million members in India in 1991. Judaism and Zoroastrianism, arriving originally with traders and exiles from the West, are represented by small populations, mostly concentrated on India's west coast. A variety of independent tribal religious groups also are lively carriers of unique ethnic traditions.
The listing of the major belief systems only scratches the surface of the remarkable diversity in Indian religious life. The complex doctrines and institutions of the great traditions, preserved through written documents, are divided into numerous schools of thought, sects, and paths of devotion. In many cases, these divisions stem from the teachings of great masters, who arise continually to lead bands of followers with a new revelation or path to salvation.
In contemporary India, the migration of large numbers of people to urban centers and the impact of modernization have led to the emergence of new religions, revivals, and reforms within the great traditions that create original bodies of teaching and kinds of practice.
In other cases, diversity appears through the integration or acculturation of entire social groups — each with its own vision of the divine — within the world of village farming communities that base their culture on literary and ritual traditions preserved in Sanskrit or in regional languages.
The local interaction between great traditions and local forms of worship and belief, based on village, caste, tribal, and linguistic differences, creates a range of ritual forms and mythology that varies widely throughout the country. Within this range of differences, Indian religions have demonstrated for many centuries a considerable degree of tolerance for alternate visions of the divine and of salvation.
Religious tolerance in India finds expression in the definition of the nation as a secular state, within which the government since independence has officially remained separate from any one religion, allowing all forms of belief equal status before the law. In practice it has proven difficult to divide religious affiliation from public life.
In states where the majority of the population embrace one religion, the boundary between government and religion becomes permeable; in Tamil Nadu, for example, the state government manages Hindu temples, while in Punjab an avowedly Sikh political party usually controls the state assembly.
One of the most notable features of Indian politics, particularly since the 1960s, has been the steady growth of militant ideologies that see in only one religious tradition the way toward salvation and demand that public institutions conform to their interpretations of scripture. The vitality of religious fundamentalism and its impact on public life in the form of riots and religion-based political parties have been among the greatest challenges to Indian political institutions in the 1990s.