Actually, having an Aadhar number does not imply that the person is a citizen - this is one of the statements present in the application form itself. So, it is possible for non-citizens to have an Aadhar number.
So Aadhar is meant for the whole world including our neighbouring citizens (and Intelligence agencies) of Pakistan and China ? Thank you for educating me, I didn't know that. Its truly wonderful and neighbourly that they get the convenience of self-registration without providing proof and customizing their bio-metrics during upload. Only Indian citizens should be held to a higher standard.