Dear Varun,

Yes, there's a payment of fees to accept the seat after the seat allotment process. You have to visit the zonal IIT for verification of documents and paying the fees. The fee is:

For general category and OBC:

Rs. 35,000 /-

For SC/ST:

Rs. 15,000 /-

You can pay the fees by internet banking, debit/credit card and nearest bank branch to you.

I hope that'll help you, Best of luck for your further career prospects.