Hii

As per the previous year cutoff of IIT BOMBAY, to get admission into Geoinformatics and natural resourse engineering, you need minimum 360 in CE/AR/AG or 315 in MN/GG/MA/PH or 450 in CS/EC/EE in OBC category.
SO since you have scored 515 in Civil and you belong to OBC, you have higher chances of getting Geoinformatics in IIT Bombay, but no confirmation can be given as the cutoffs are yet to be released. Please wait for the cutoffs and hope for the best , you have a very high chances of getting your desired course and branch.

Hope this helps
Thanks!!