I can never stop suggesting people join ISI Kolkata by any means. It’s a magical place for math lovers and has given birth to many world-renowned Mathematicians. Even the offered SERC at IISc cannot be compared to ISI. 

Whenever you are choosing a college or even a branch, the best way to determine the best option is to check the faculty profiles. People who choose colleges solely on the basis of placements realize the true scenario to be way different than expected and end up regretting their decision. So, don’t aim for becoming successful only, rather become talented and skilled enough that success seeks you on its own. Stop focusing on placements, focus on other major things, and good placements will be well on your way!