In doctoral researches, we are not allowed to research literature using the philosophical thoughts of Indians. We are allowed to use only the Western philosophies or schools of thoughts.
We could use Indian sources here in the United States, if they were relevant, at least in the doctoral program at Oklahoma State University that I graduated from.
As far as I know, there are no such restrictions in India. Well, you cannot simply include Indian philosophical thoughts in totally unrelated fields. Anyway, since Charley Samuel made this allegation he has to clarify further.