For an Indian beginner playing Hindustani Music which recorder is the best - soprano or alto with German or Baroque style ?
Any of those would work. Soprano or alto is just a matter of taste- which sounds better to you? German or Baroque fingering depends a bit on the keys you intend to play in. German is easier to learn because the note F (on the soprano- Bb on the alto) doesn't have a forked fingering. But if you need the notes F# (or B natural on the alto) often, then you will have problems. I would say go with the Baroque, in case of doubt, because it's more flexible.
I always recommend alto for beginners -- they are easier and more forgiving to play sweetly. Never choose German fingering -- those recorders are never in tune with themselves, because of the compromises made for "easier" fingering. So, alto with Baroque/Modern fingering.
I know nothing about Hindustani music, sorry - but (in Western notation) what range of notes would you need?
If a lot of the pieces you want to play go below the F on the bottom space of the treble clef then a soprano would be better;
X:1 T:Soprano recorder M:4/4 L:1/4 K:C C-g
if however you tend to start at or above the F and go up beyond the g at the top of the treble stave, they sit more comfortably in the alto recorder range.
X:1 T:Alto recorder M:4/4 L:1/4 K:C F-c'
Both instruments of course go higher than the range I have shown, these examples are just to help you choose the best option.
And as others have said avoid the German fingering recorders, baroque fingering is always the system to go for.