No it is not P. biaurita at all! Entirely different. In P. biaurita the bases of the pinnules are much more deeply joined together, so the base of the interpinnular sinus is several mm or more above the pinna-midrib. But in this species you can see the pinnules are cut down to the pinna-costa. Also the ultimate segments in P. biaurita are not so narrow. Lowest veinlets anastomose in biaurita, not in this species.
The many very narrow pinnules show it to be P. blumeana - and as the photo is out of focus and shows the wrong surface (top surface is needed for the compound Pteris species) and one can't see the pinnule-apices either - it is something the collector can do to confirm it as P. blumeana.
1. There should be long thin white setae on the segment-midribs (pinnule-midribs) on their top surface - though if the specimen is dipped in alcohol, they are easily deciduous.
2. The tips of the ultimate segments (pinnules) should be non-mucronate, just rounded (sometimes very slightly sub-mucronate, but not usually).
P. blumeana is quite common in the hills of South India, and not usually at very high altitude, lower in the E. Himalaya, too. It has usually been misidentified as P. aspericaulis, which latter does not occur in peninsular India.
All the best,
Chris Fraser-Jenkins, Portugal.