Hello Anuj,

              Generally one needs to have at least 500AIR to have chances in PSU, but you have 289AIR, and you're OBC. You wouldn't even need the category support to get any of the PSUs. Cutoff changes every year but based on the last year and 2017 cutoff, you have very good chances in NPCIL, BSNL and slight, NTPC. But remember, the actual selection is based on GD and PI, not your AIR, so if you flunk in the interview, no matter your good rank, you'll still be disqualified. 

As for IITs and NITs, you can have any college you want. The cutoff isn't released yet so we can't be sure but rest assured, the ball is in your court and you have many options to opt.

Last year, the cutoff for Instrumentation was 33.3 for OBC. You have a great chance in all the NITs, CFTIs and some of the IITs (just in case cut-offs are high). 

Refer this link to know your chances in colleges: https://engineering.careers360.com/gate-college-predictor

I hope this helps in answering your query. Leave a comment if you have any more question.

Hey Anuj.

Congrats for ur good rank in the GATE exam.

See the rank u have got is enough for u to get admissioned in the IITs for pursuing ur higher studies in the field of ur interest under ur OBC category. U can also apply for other good govt colleges and private institutions for ur admission. About getting PSUs u can also apply for that to pursue ur job career.

I m providing a  link of college predictor. Hope it help u.

https://www.google.com/url?sa=t&source=web&rct=j&url=https://engineering.careers360.com/gate-college-predictor&ved=2ahUKEwjtgsq38ovhAhWDiXAKHSqhDr8QjBAwAnoECAgQCg&usg=AOvVaw1xiFTORDwDEpBZmadY5ZwG

Ask if any query. Good luck