hi koushik,

                You have very less chance of getting any good govt. colleges out there.But you will surely get the private colleges given below with mech engg branch:-

Narula institute of tech.

Rcc institute of tech.

Haldia institute of tech

BP PODDAR institute.

and obviously the other private colleges like ABACA,AMITY,AOT,etc.

Hope this helps you.

BEst of luck.