Hinduism was one of the major Eastern religions on Earth. Its adherents were called Hindus. (PROSE: Doctor Who and the Crusaders) They believed in reincarnation. (TV: Rendition)
Hindu religious teachers were called swamis. (AUDIO: The Case of the Gluttonous Guru, Hounded, PROSE: The Death of Art) Wandering Hindu holy men were called sadhus. (TV: Demons of the Punjab)
Navratri was, as the Tenth Doctor once told Donna Noble, a "Hindu festival [with] lots of dancing." The Doctor once celebrated Navratri with Kamalnayan Bajaj by bringing along some fireworks. (PROSE: Ghosts of India)
Anji Kapoor was a Hindu, but hadn't visited the temple since she was a child. (PROSE: The Crooked World)
A holy book in the Hindu religion was The Gita. It discussed the life of Krishna, (PROSE: Ghosts of India) an incarnation of the god Vishnu. (PROSE: Dharmayuddha) Other Hindu deities included Shiva (PROSE: Ghosts of India, Dharmayuddha) and Kali. (COMIC: The Swords of Kali)
A Hindu tradition was to tie a couple's hands together during a wedding ceremony. Yasmin Khan performed this tradition during the wedding of her Muslim grandmother Umbreen and her first husband, Prem, a Hindu. (TV: Demons of the Punjab)
Pythagoras was trained by the Hindu sages in India. (PROSE: The Pythagoras Problem)
India was a mainly Hindu nation, whereas the region that would become Pakistan was mostly Muslim. The Partition of India on 17 August 1947 created a state for Muslims to live. Religious conflicts between Hindus and Muslims were frequent in this period and marriages between individuals of the two religious were shunned. Manish, a Hindu, killed his own brother Prem and Bhakti, the holy man that was to perform his wedding, because Prem intended to marry a Muslim, Umbreen. (TV: Demons of the Punjab)