Assuming you are from General Category to secure a seat in Civil Engineering M.Tech at IIT Delhi, the cutoffs in GATE CE for various M.Tech specializations are as follows

Construction : 770

Structural : 820

Water resources : 675

Transportation : 709

Incase you are from OBC Category you can expect a relaxation of atmost 40-50 points from the Score mentioned above for GENERAL Category. As you see Structural Engineering followed by Construction Engineering & Management are two of streams having direct applications in the Infrastructure Industry and Placement prospects with Companies like Tata Projects, L&T as well as Top PSUs and Research Organizations like ISRO, BARC, hence their demand and high cutoffs.

For more information about Gate Cutoffs at various IITs and various streams do follow the link below

https://engineering.careers360.com/articles/gate-cutoff