Hi Sneha,

I would recommend you to retake the NEET examination as 171 is quite low for MBBS admissions. I understand it might take time to re-learn those PCB concepts, but if you're looking for a decent college I would strongly advise you to retake the exam. 

As per taking a private seat, I am not sure about that procedure.

Or you can either try one of the following options: 

1) Look at study abroad programs in which you can do your MBBS from a different country like Russia or some other country. 

2) Drop  another year for NEET. And expect yourself to do well next year but the only problem is that people are usually disheartened after failing in such competitive examinations. So go for it,  if you feel confident and if you know that you'll clear NEET no matter what otherwise learning stuff with no confidence on yourself can cause you to fall behind in your studies. 

3) Change your field! You can look to go into research fields by taking admission in B.Sc. or you  can study for CLAT if you feel that medical field is not working out for you. I have seen people leaving engineering/medical preparations for CLAT, and they were successful at accomplishing a great rank (even under 100 AIR)… People say that it's comparatively easier than engineering/medical so it might work out for you.

And most importantly don't waste your year, if you are truly passionate about being a doctor then only take this step of dropping a year or else you are wasting your time. If you do then study hard! And try to score 550+ for decent colleges. 

Don't feel disheartened, keep trying and keep learning! All the best for your future!

Hope this helps!

Good luck! :)