Hi Babutv and rocky,
Overseas citizenship of India is nothing but a life long visa to India for people of Indian origin who has taken up citizenship of other countries ( excluding Pakistan and Bangladesh). It will avoid queing up for visa every time before they come to India. It also gives you opportunity to work or invest/run business in India, with all the legal protection. But i think there some restrictions, like not entitled to vote, contest elections, or purchase agricultural land etc. It is obviously not full citizenship or dual citizenship.Thanks