hello aspirant,

it is possible to get a phd in nit or iits without gate. some iits have their own written exam for phd's and if you have good score in your bachelors and masters you may get direct admission. there are some sponsored seats in iits forphd also. you need to check the official websites of iits and nits as it varies year to year. o through the below link for further information.

https://www.careers360.com/question-is-there-any-iit-or-nit-which-give-adimission-in-phd-directly-on-the-basis-of-gate-score-without-their-written-test