Yes you can write your Indian DGCA ATP exams provided you hold an Indian CPL with a multi engine endorsement or
Hold an ICAO issued full ATPL
You will need to first get a Computer Number issued by the Indian DGCA first to write the exams
I believe frozen ATPL refers to someone who has passed all their ATP written subjects but does not hold the experience requirements for issuing the same
The Airlines in India do not require a fATPL for applying for an entry level first officer position