Dear

With pcm subjects you can think these challenging and interesting options

Environment science
Nanotechnology
Aerospace engineering
Actuarial science
B.pharma
Food technology
Physics Hons

But choose the field with your caliber and interest . Don't choose Engineering degree only for tag name if Engineer.

All the Best

Go for IITJEE preparation. It will be the best option for you if you get some respectful marks in PCM.