Hi Padamshree

Yes, you can pursue M.Tech in Astro Physics even if you are doing graduation in ECE but you have to actually check the colleges and institutes where this programme is offered as it is rare.

Refer to the link given below :

https://www.careers360.com/question-what-to-do-if-im-interested-in-astrophysics-and-i-reside-in-india?icn=question-title-details&ici=question-detail-page

Hope this helps you !