Declared religious affiliation
India is a Hindu-majority state (about 80% of the population) but is home, in absolute terms, to one of the largest Muslim populations in the world — more than 170 million people according to the 2011 census, more than in most Muslim-majority countries. It also has large Sikh (concentrated in Punjab), Christian (especially in Kerala and the North-East) and Buddhist communities (historical heir to Buddhism, also strengthened by the mass conversion of former untouchables led by B. R. Ambedkar in 1956), as well as a small but influential Jain community. The 1950 Constitution makes India a secular republic (constitutional "secularism", a term explicitly added to the preamble in 1976), guaranteeing freedom of worship to all faiths.
Census of India survey · Total population reporting a religious affiliation
Source: Office of the Registrar General & Census Commissioner of India · 2011Latest available religion data, from the 2011 census (the next decennial census, planned for 2021, has been postponed indefinitely).