Since you, yourself, are outside of the United States, I cannot provide you with advice as to whether your local authorities or phone company can do anything about this call.
However, I can inform you that "91" is the country code for India. If you are using a caller ID unit or phone that was designed for the U.S. markets where 7 and 10 digit numbers are universal, those units will garble the telephone numbers of any country that are not standard 7 or 10 digit numbers and/or not correctly show their country of origin.