Hi There,

Aadhaar is not a proof of citizenship. It is written on Aadhar Card that "Aadhaar is a proof of residence not citizenship". Any foreigner who presides in India can apply for Aadhar card. It is for identity not for citizenship. If you son have Indian citizenship then you can give his nationality Indian while registering for CBSE. But if his nationality doesn't changed or if he is still an American citizen than it is not possible to give a nationality as Indian. Citizenship of India by naturalization can be acquired by a foreigner (not illegal migrant) who is ordinarily resident in India for 12 years. Indian citizenship can be acquired by registration, for a foreigner who have lived 7 years in India as a resident. It also extends to persons of Indian origin who are residents in any country outside undivided India and minor children of persons who are citizens of India.

Thank you