hi!To become an astronaut in india you have to follow the following steps:

1. you should be a permanent citizen

2.There are no specific height requirements, but you should be in good shape with satisfactory medical history, normal blood pressure and perfect vision sharpness

3.A bachelor's/master's/PhD degree in STEM field or aeronautical/aerospace engineering is the expected qualification you must possess to become an astronaut

Here is a list of top colleges to pursue this career:

IIT Roorkee

IIT Delhi

Amity University Noida

SRM University, Amravati

IIt kharagpur

After graduation you can appear in the entrance examination conducted by NASA for recruitment. you can also find employment in ISRO, through openings conducted by them by clearing the Joint Entrance Examination which is set by the IITs.