Dear Sourav,

Sorry to inform you that in both IOCL or ONGC you can not apply for manufacturing engineering. As, per the given details I followed up from, and they are:

For IOCL:

https://www.iocl.com/download/Recruitment_of_Engineers_Officers.pdf

For ONGC:

https://www.flickr.com/photos/182261284@N06/48149403152/in/dateposted-public/

As the Manufacturing Engineering falls under Mechanical Engineering, so, applying for Mechanical Engineering in IOCL and ONGC excludes Manufacturing Engineering from the entrance exam of GATE. For further confirmation, you can call IOCL and ONGC helpline numbers.

Furthermore, there are many profound companies for you like:

Birla Power Solutions, CISCO, Burckhardt Compressor, and automobile industry, etc.

I hope that'll help you, Best of luck with your further career opportunities.