According to US's rules of chargeability an immigrant shall be charged to the numerical limitation for the foreign state or dependent area of birth, unless the case falls within one of the exceptions to the general rule of chargeability provided by INA 202(b). One of the exceptions is
Exception for alien born in foreign state in which neither parent was born or had residence at time of alien's birth. An alien who was born in a foreign state, as defined in § 40.1, in which neither parent was born, and in which neither parent had a residence at the time of the applicant's birth, may be charged to the foreign state of either parent as provided in INA 202(b)(4). The parents of such an alien are not considered as having acquired a residence within the meaning of INA 202(b)(4), if, at the time of the alien's birth within the foreign state, the parents were visiting temporarily or were stationed there in connection with the business or profession and under orders or instructions of an employer, principal, or superior authority foreign to such foreign state.
For an alien born in India during his foreign parent's graduate studies, what are some good points/documents to argue for charging the alien to one of her parents' country of birth? The foreign parents were sponsored by their own countries (as opposed to India) for their graduate studies. In other words, you can argue that they were employees of their own governments.