This depends on the Course that you want to study in India. For example, for Candidates who want to pursue Undergraduate Engineering programmes offered by NITs, CFTIs and Punjab Engineering College, admission is done through DASA. This stands for Direct admission of Students abroad. But if this is regarding MBBS, BDS, then there is a separate quota for NRI Cadidates which is upto 15% under All India Counselling and also 85% State Counselling. You do not need your parent's domcile certificate for that. Those Candidates who wish to apply under NRI sponsorship must have a blood relation to the financial supporter whether it is the mother. father, sister, brother, aunt or uncle. For this, the documents you will need are Valid passport, Student visa, NOC from the Ministry of External Affairs, Non-Objection Certificate issued by the Ambassador, Vaccination Certificate , Health Certificate, Health Insurance Certificate, Community Certificate, Community Certificate and other academic documents.