Wait, you had to have your negative PCR test in hand at time of departure from the US? Was that an airline rule or India rule?
My experience when I flew Air India JFK-DEL back in January was that AI didn't require me to show test results at departure (although I did have them with me), only needed to show upon arrival in DEL. Has something changed?

My parents are scheduled to fly on Qatar Airways IAD-DOH-AMD this coming Tuesday evening (5 Oct), so they have a PCR test scheduled for Saturday 2 Oct per the 72-hour rule. However, with the standard "2-4 day" turnaround that all testing sites quote, plus there being a weekend, there is no absolute guarantee they'll have the results in hand before departure, it's possible they will arrive while they're en route, I was going to email the results so they'd have them upon arrival.

So per this post I'm now worried that they could be denied boarding at IAD if tests results haven't been received. Any thoughts on if my fears are founded or unfounded?