Why India has no citizenship for the Tibetan refugees who have been there since 1959.?

Without the rights and the priveledges of an Indian citizen, the Tibetans are a disenfranchized group in India. Nearly 50 years after being exiled from their homeland, India has bared the Tibetans from participating in their Democracy. Even the Tibetans born in India are kept a bay. This policy of "demorcracy for some and not for others" are not only bad for the refugees but it potentially undermines the democratic integrity of India.