According to the current government guidelines it has been made mandatory to do your web check-in ahead of arriving at the airport for your flight, and the same holds for IndiGo
Airlines as well. If you do your web check-in between 48 hours to 60 minutes prior to your flight’s scheduled departure then you do not have to pay any additional cost. But the airline charges a facilitation fee of INR 200 for any assistance with airport check-in.
Indigo Group Booking