Dear Rahul,

There are some good govt. engineering colleges in Mumbai which accepts jee main score.

You can check out the following link:

https://engineering.careers360.com/colleges/list-of-government-engineering-colleges-in-mumbai-accepting-jee-main

Now coming to your second question,It's totally depend on the govt. that how many Nits/IIITs should be in the state and in which city Nits/IIIts they should be made.

Am I able to clear your doubt? If you have any other questions,let me know in the comments.

And If you are jee aspirant and want to predict colleges based on your percentile please go through the following link:

https://engineering.careers360.com/jee-main-college-predictor?icn=QnA&ici=qna_answer

Good Luck :^)