What is the significance of the Indian element in "The Waste Land"?

In his popular modernist poem "The Waste Land," Eliot makes various references to Greek mythology, Shakespeare, and many others, and even incorporates some Phoenician and Indian elements. He masterfully reconstructs all of them.
Thus, Eliot finishes the poem writing:

Datta. Dayadhvam. Damyata.Shantih shantih shantih

"Datta, Dayadhvam, Damyata," refer to the concepts of "giving, compassion and control" of the ancient Indian religious and philosophical texts Upanishads, which are based on the ideas of Hinduism and Buddism. According to the texts, all people must follow these three concepts in order to achieve inner piece, and the Gods and nature can enable this. The word "Shantih" is actually the formal ending of the Upanishads, and literary means "inner peace."
If Eliot alludes that the 'Waste Land' is, in fact, the modern world which was reshaped by the First World War, then, with the use of the sacred chant "Shantih," Eliot ends the poem with a hopeful and spiritual tone, implying that peace and harmony can, in fact, be achieved. This is how he breaks the traditional form of writing poetry and leaves his typical modernistic stamp.