Hello

Congrats you have got a very good rank

You will be an iitian

Coming to the cutoffs based on previous year statistics

Top 3 iits Bombay Delhi and Madras

Bombay closing rank is 139 for civil engineering at last round

For Delhi it is 170

For Madras it is 220

So based on previous year statistics

IIT Madras is best choice you have

You can definitely  get other mediocre iits also for civil no doubt