IIT

With just JEE, you can't get admission in IITs. You have to appear for JEE advanced and then based on your performance, you'll get admission in IIT Madras.
JEE main is for NITs.
To get admission in IITs, you must appear for JEE Advanced.

Please visit on this site first-
https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor&ved=2ahUKEwidkeeQ-bvhAhVCeysKHeTvAgYQFjAAegQIBBAB&usg=AOvVaw1N9BzFtyUCP4JU-2UQHQ0H.

Kotak is the best city for preparation, because there are so many coaching institute and environment for studies.

There are many ways where you can get previous years' question papers of IIT. You can either buy books like 42 years previous years'question papers of IIT from reputed publications like Arihant, Engage, Odisha, etc. Or you can get previous years' question papers of IIT from online sources like from BYJU's, Shiksha, etc. All the best. Feel free to clarify any query.

Hello Manik,
Yes, of course. In fact, it is very nice to hear from you that you are interested in the research in Environmental Science. This is the subject which is most important for the very survival of human race in this world. Graduating from IIT will definitely give you a firm Foundation from which you can seek research oriented jobs in either a government lab or some other place. You can even think of joining integrated M.Tech come Ph.D course in environmental Science where in research will be part of your grooming and your studies. Best wishes to you.

Mechanical Engineering is one of the oldest branches of engineering with an extensive application platform that ranges from design and development to construction of physical devices. In 2013, the intake for mechanical engineering was 1,125 out of total 9,867 seats were available with IITs and ISM Dhanbad.

If you think you can work hard, then you should. If not, then go for a local college.

Yes, you can give Mains 3 times and Advanced 2 times.

The minimum eligibility is 60% in class 12th for general category. For IIT and NIT admission, you have to attempt JEE and JEE Mains and the cut varies every year.