Hello aspirant

Basically according to sources , highest paid job in ISRO is ISRO space  scientist engineer  .. There are many fields in particular scientist engineer in isro and the salary basically varies from 95000 to 6 lakh per month .. So not sure about 1 crore per annum but it is very highly paid job in india.

In iits and nita , you can get placement and job easily is you study very well and your all concepts should be clear ...

For this mechanical engineering branch is best because it contains all that is design , structure , managed it , and also structures of various engines that is very imp in this field .. Electronics , computer science , and electrical branches are also very good and eligible branches for become scientist engineer in ISRO

Hope it helps