Is it better to choose mechanical engineering at IIT Kharagpur or civil engineering at IIT Bombay?

It really depends in what you want to do in life... Choosing Civil over Mechanical would make you a pathetic Mechanical Engineer, if a Mechanical engineer is what you want to be, and vice versa. The moral of the story is, don't just choose your education based on the institution. 

The institute will stay with you for just 4 years, but the course you choose will stay with you for life... And if you plan to do something totally different (neither related to Civil, nor Mechanical) why the heck are you wasting these four wonderful years studying something that

you won't use in your life? 

In that case, you'd

better choose another course and leave these seats for a more deserving candidate; for someone who'd like to study these subjects because he/she likes those subjects, not just for

adding a prestigious degree to their visiting card. 

All the best. And always remember the

Telebrands tagline: " Choose wisely, live

well." :)