Hello Chandan !

For engineers in Indian Army there are three major constituents namely Combat Engineers, MES (Military Engineering Service) and Border Roads.

1. The main role of combat engineers is to provide mobility to own forces by constructing bridges, tracks and helipads; on the other hand the Corps denies the same to the enemy by creating obstacles such as laying mine-fields and demolition of bridges.
2. The military engineers are mainly responsible for the design, construction and maintenance of all works, buildings, airfields, dock installations, etc.
3. The Border Roads Organisation is another major arm of the Defense services which is playing a vital role by constructing national highways, airfields, buildings and bridges.

If you want more information regarding eligibility and exams related to this field please feel free to ask.

Hope it helps !