Diversity characterizes Indian religion: the worship of Shiva and Vishnu in many forms, the philosophy of rebirth and the quest for nirvana, interwoven with a bewildering variety of local cults and practices. The subcontinent has seen many developments of indigenous inspiration, such as Buddhism and Jainism, while other strands have been added by the many groups of historically attested outsiders who have settled there. Practices, beliefs, and devotion to the worship of particular deities are often strongly linked to group identity. Going back into the Indus period, we should expect religious pluralism already to be present, given the multicultural background of the Harappans and their long-standing links with their many neighbors.
Though much about Harappan religion is obscure or speculative, the evidence that exists does allow something of the broad picture to be reconstructed. The abundance of water facilities in Harappan settlements and the Great Bath at Mohenjo-daro show that the use of water played a key role in religious practice, most probably being used in ritual purification, and the icono-gaphy suggests that terrestrial waters, with their fish, were closely related in belief to the waters of the heavens in which swam the stars.
The Harappan seals were used in official contexts and should therefore reflect iconography of the official belief system shared by the people of the Harappan state. In this we see evidence of the worship of a male and a female deity, probably taking many forms, closely linked to the male and female principles and to the natural world, especially that of trees, particularly the pipal, and powerful animals, particularly the bull/water buffalo and the tiger. Animals not known in the real world also populated that of the gods, particularly the magnificent unicorn. Rites associated with the worship of these deities and spirits included processions, offerings, and probably shamanistic practices.
In addition there seem to have been lesser cults, practiced by certain groups within Harappan society or in certain regions, the latter in particular reflecting the differing cultural backgrounds of the Harappans' ancestors. In the Indus Valley, the ubiquity of female terra-cotta figurines, including Mother Goddesses, links to the long tradition of their manufacture by the people of the Indo-Iranian borderlands. In contrast, in Gujarat and the Sarawati Valley where many people were descended from indigenous hunter-gatherer stock, some rituals, probably both in public and in the home, involved sacrifices made through fire.