As per reply from [email protected], person resident in India as defined under Foreign Exchange Management Act 1999 are eligible to invest in SGB -
* Link to form referenced in the above email
As per the Foreign Exchange Management Act, 1999 (FEMA) (Page 4-5), a company is also considered as a person and can be considered to be a “person resident in India” if it is incorporated in India (for more information, refer to this) -