My experience in DEL was that check-in agents start to arrive at the counter 2.5-3 hours before.
For 2 times I arrived with a domestic flight, around 8pm. I can tell it's a real long wait in the check-in area, nothing to do or see and
nowhere to sit....tried it
Avoid arriving early! Just 5 minutes by taxi there is a nice Radisson with 24 hour serviced lobby bar. If you're daring enough you can head down stairs for a quick "free" shower. But beware of staff checking for non-hotel guests
