dear aspirant,hope you are doing well,now coming to your question,The future scope of mechanical engineers in India remains as expected.There is always a consistency for the past decades.This is,also, going to be true for the decades to come.
So many companies are good for a mechanical engineers, a few of them are as follows:
ABB group,BAARC,BHEL,BEML,Bosch group, BNPM, BPCL, Caterpiller, CELHPCL,Coal India Ltd,DRDO,Ford group,GAIL,GSECL,HPCL,Hundai group,IOCL,IPR,Kirlosker group,L&T group,MDL,MECL,Mahendra & Mahendra group,NFL,NALCO,NHPC,NLC Ltd,NTPC,Oil India,OPGC Ltd,ONGC Ltd.Power grid,Reliance groups,RITES,Tata group,THDC,TVS group,WBSEDCL,etc.
A mechanical engineer to be placed in a core company should have the basic ideas in the following subjects (with some practical exposure):
1) Engineering drawing,
2) Engineering mechanics,
3) Strength of materials,
4) Engineering materials,
5) Materials science,
6) Finite elements method,
7) Fluid mechanics,
8) Solid mechanics,
9) Project management,
10) Total quality management,
11) Computational Fluid Dynamics,
12) Solid waste management,
13) Green technology,
14) Fracture mechanics,
15) Machine drawing,
16) Manufacturing methods,
17) Design of machine components,
18) Kinematics of machines,
19) Dynamics of machines,
20) Thermodynamics,
21) Applied thermodynamics,
22) Heat and mass transfer,
23) Rapid prototype manufacturing,
24)Control engineering,
25) Industrial engineering,
26) Quality assurance,
27) Reliability engineering,
28) Operations research,
29) Operations management,
30) Supply chain management,
31) CAD/CAM,
32) Automation,
33) Nano technology,
34) Mechatronics,
35) Theory of machines,
36) Turbo machines,
37) Theory of plasticity,
38) Theory of elasticity,
39) Foundry technology,
40) Financial management,
41) Photo lithographic process,
42) Sputtering technique,
43) Limits and tolerances,
44) Machine tools, etc.

hope this will help.