If you are arriving from a flight in Europe/UK, you will have to get an arrival PCR test at your own expense. My understanding is that when you fill out the Air Suvidha form, if any of the two entries (listed below) are true, then the airport authorities will herd you to the area where you have to get tested.
1. Flight Number (indicating arrival from Europe)
2. Last 14 days travel history (indicating Europe/UK)