B.Tech Scope

Mechanical engineering is known as the evergreen branch among all the other branches of engineering. Traditionally, mechanical engineers have to deal with concepts such as mechanics, thermodynamics, robotics, kinematics, structural analysis and fluid mechanics with their applications in the automotive sector, power sector, refrigeration and air conditioning sector, aerospace.
Nowadays, the scope of mechanical engineering is expanding beyond its traditional boundaries and is more of inter-disciplinary in nature. Mechanical engineers are focusing their attention towards new areas such as nanotechnology, development of composite materials, biomedical applications, and environmental conservation. With this shift in paradigm, the new job avenues have been opened for the mechanical engineers.
On the other hand, I would suggest you to pursue computer science engineering with diverse specialisations. If you go for computer science engineering, you will get really worthy salary packages, avenues to go abroad and you can work anywhere. Computer Science has a very wide scope. Indian IT companies such as Wipro, Infosys, TCS, Pani, HCL, etc. have been able to garner gains even during the recession and have hired a number of computer professionals. Even the MNCs look for good computer engineers from India.
A few college recommendations for you are: IITsBengal Institute of Technology, KarnatakaUTM, Shillong