Hi

You can sure do an M.Sc in Physics first, and then go for a specialization, i.e PhD in Astrophysics. Infact, it also meets the eligibilty criteria for PhD.

There is also an integrated MSc+ PhD in astrophysics offerered at TIFR, have a look at this link- https://www.careers360.com/university/tata-institute-of-fundamental-research-mumbai/msc-and-phd-astronomy-and-astrophysics-integrated-course

Other colleges:

https://www.careers360.com/university/indian-institute-of-science-bangalore/phd-astronomy-and-astrophysics-course https://www.careers360.com/university/university-of-delhi-delhi/phd-physics-and-astrophysics-course