Both are the decent college but As per the analyzing report of Careers360 Faculty of Law, University of Delhi, Delhi has AAAA+ rating which means outstanding & GLC Mumbai has AAA+ rating which means good. This rating is based on the research of the colleges on placement, Faculty, Study Environment etc. You can check the genuine reviews of the colleges with the given below links, It will help you to choose a best option for you.

https://law.careers360.com/colleges/faculty-of-law-university-of-delhi-delhi

https://law.careers360.com/colleges/government-law-college-mumbai

You can also check about to compare the colleges with the given below link.

https://www.careers360.com/compare-colleges

Good Luck!