Hi Aspirant!
According to previous year cutoffs the maximum rank under which cadidate got into IIIT in Round7 with OBC category is around 18k to 21k,but your rank 40k is far from that range.Hence it would be impossible for you to get into any NIT or IIIT.Although you can try your luck in GFTI or in CSAB special counseling.

You can follow these Career360's articles for a better understanding of cutoffs.

NIT: https://engineering.careers360.com/articles/nits-cutoff-for-top-btech-branches

IIIT: https://engineering.careers360.com/articles/jee-main-cutoff-for-top-iiits

GFTI: https://engineering.careers360.com/articles/jee-main-cutoff-for-top-gftis

Also, you can follow up this Career360's article for more information on CSAB SPECIAL COUNSELLING:

https://engineering.careers360.com/articles/csab-special-round-for-nits-iiits-and-gftis

Also don't forget to check out the Career360 College Predictor to know your college admission chances based on your JEE Main Rank, Home State, Caste, Gender, etc. https://engineering.careers360.com/jee-main-college-predictor?icn=QnA&ici=qna_answer

HAPPY HUSTLING!