nowhere has dgca mentioned about that so precisely.
however, they ask for a 10+2 pass with maths n phy.
you are 10+2 pass.
you have maths n phy now.
so i dont think will be a big problem. but only any dgca personnel can give you exact info about this, coz yours is a special case.
if i were you, and even if any dgca officer would have said me that its ok as long as a am passed in phy n mths, i would still try to pass in hindi and keep the whole thing clean. who knows, in future, by any chance anybody can raise voice against you.
no harm and really not so much pain to study and pass hindi.
all the best.
by the way, i have a friend who had phy chem and bio in his 12th. he is from ahmedabad (near to your city). and he was trying to write maths exams in open school. if you need his details, pm me. may be you guys can share thoughts, being in the same boat.