The main religion in India is Hinduism accounting for about 80% of the total population. The next is Islam accounting 13% and the other native Indian religions include Buddhism, Jainism, Sikhism accounting for 3-4% of the total population. About 2% of the Indians belong to the religions of Christianity, Zoroastrianism and Judaism. The religious diversity in India extends itself to the highest levels. It has been declared in the Constitution of India as a secular state and all citizens are permitted to freely worship and propagate any religion or faith.
Hinduism's origins consists of the Indus Valley Civilization, the Vedic religion of Indo-Aryans, and other Indian civilizations. Rigveda is the oldest surviving text of Hinduism and was produced during the Vedic period around 1700–1100 BCE. The great sacred epics belonging to Hinduism Ramayana and Mahabharata were written roughly from 500–100 BCE, although these were transmitted orally for centuries prior to this period.The term Hindu, derives from the Sanskrit word, Sindhu, (the Indus River), and refers to a person from the land of the river Sindhu.
Islam, a monotheistic largest minority religion in India revolving around the belief in one God and follows the example of Prophet Muhammad. India is home to world's third-largest Muslim population after those in Indonesia and Pakistan. Majority of Indian Muslims are found in Jammu and Kashmir and Lakshadweep, with high concentrations in the states of Uttar Pradesh, Bihar, West Bengal, Assam, and Kerala. Sunni muslims constitute nearly 80% of Indian Muslims.
The third largest religion of India Christianity, a monotheistic religion moving on the life and teachings of Jesus as presented in the New Testament; make up 2.3% of the Indian population. Christians are mostly found in North-East India, Goa and Kerala.
Buddhism is a dharmic, nontheistic religion and philosophy. Indian states of Arunachal Pradesh, the Ladakh region of Jammu and Kashmir and a large minority (40%) in Sikkim form majority populations of Buddhists.
Jainism is a nontheistic dharmic religion and philosophical system originated in Iron Age India. 0.4% of India's population are Jains, and are mostly concentrated in the states of Gujarat, Karnataka, Maharashtra, and Rajasthan.
Sikhism started in 16th century in North India with the teachings of Nanak and nine successive human gurus. Punjab, a Sikh majority state is undoubtedly the spiritual home of Sikhs. Sikhs are also concentrated in neighbouring New Delhi and Haryana.
Followers of Zoroastrianism (Parsis in India) contribute approximately 0.006% of the total population of India, with high concentrations in and around Mumbai.
A very small community belong to Indian Jews.
The preamble to the Constitution of India proclaimed India a "sovereign socialist secular democratic republic". In the 42nd Amendment Act, 1976 , the word secular was inserted into the Preamble It tells equal treatment and tolerance of all religions. The constitution enshrines the right to practice, preach, and propagate any religion.