80% of the population is Hindu, 11% Muslims and the rest are Sik, Christian and Buddhist, Jain, etc ...

Several of the "great" religions originate in India, including Hinduism and Buddhism. Some religions are unique to India such as Sikhism which represents 2% of the Indian population.
In the history of the country, religion has often played an important role, now recognized by law. It is an essential element in the life of Indians, many men dedicate their lives to it. By entering the temples, you have the opportunity to regularly see Brahmins, Hindu priests, reciting their prayers or making offerings.

You can notice that Hinduism is by far the most widely practiced religion, considered one of the oldest religions in the world. There are hundreds of gods and goddesses (it is even said that there are 30 million!) In the Hindu religion, the most famous of which is Ganesh with an elephant head. They worship them as they wish.
The three main gods, which form the Hindu trinity are Brahma (creation), Vishnu (preservation) and Shiva (destruction). Each deity has its temples and religious celebrations.
Since the cow is sacred (considered their mother) to Hindus, it is forbidden and unthinkable for them to eat it.
As far as the Muslim religion is concerned, it is pork that is forbidden to eat.

Hindus believe in karma which would influence their reincarnation either in a higher caste (good karma) or in animal (bad karma).
There are four groups of castes: the Brahmans (priests), Kshettriya (warriors), Vaishiya (traders) and Shudra (laborers).
Jati (births) correspond to professional activities (weavers, potters ...) or sometimes ethnic. The out of castes or untouchables are considered as impure by the other communities. These are social rites that date back thousands of years and continue, despite the adoption in 1950 of the Modern Constitution, which does not officially recognize the caste system.