Hello Sidharth,

Since you have not stated to which category you belong to, I would assume you belong to general category. You have scored 615 in Mechanical engineering. There is a cut throat competition in Mechanical engineering and generally in all colleges the cut off for Mechanical engineering is the highest. 

Your rank is 5744, and to get admission in IITs your rank should be below 1500. The cut off for all the older IITs goes upto 800 and you must secure upto 800 marks to be in the IITs for M.Tech. 

At this rank you may get some of the NITs like NIT Surathkal or NIT Tiruchirapalli but you may not get your dream specialisation. You can try for admission in NIT Durgapur or NIT Rourkela or NIT Jamshedpur. Depending upon how many people apply and the number of seats in these institutes, you have a fair chance of admission in these colleges. 

All the best.