Hi Vignesh!
Mechanical engineering is one of the oldest branches of engineering. This field of engineering is the broadest of all engineering fields,  job are plenty and unending only if you're skilled enough. You can find employment in both government as well as private sector.

There's definitely a saturation of engineers today who are not employable.
For you to have good scope in any field, you need to stand out in the crowd!

Mechanical engineering is the evergreen branch among all other branches of engineering. It deals with the concepts of mechanics, thermodynamics, robotics, kinematics, structural mechanics, fluid mechanics, power sector, refrigeration, air conditioning sector and aerospace. As you can notice Humans are going to need all of this and more when it comes to hardware in future too.

It totally depends upon how you groom yourself as an engineer by the end of 4 years.

Hope this helps :)
Best of luck!