Hello Manoj,

I am sorry to say that with your current rank in JEE Adv 2019, it is not possible for you to get any IIT or IIST. 

IIST is a very good college and requires higher marks in JEE Adv. The cutoff for 2018 in B.Tech- Aerospace Engg. was 34.17% 

Moreover, for qualifying in an IIST, you will be needing at least 20% in aggregate marks and 5% in PCM individually.

Hope this helps you in understanding the scenario.

Good Luck!