It’s also worth noting that with the early retirements of the 777s, in the near term DL will actually be short on widebody planes for making these long haul international flights. Thus it is very unlikely they will use one of their limited A350s on an India flight (at least in the near term).

As more A350s are added to the system, DL will be re-evaluating where to add (or likely re-add) routes to. That being said, the A350s are at a competitive disadvantage for long and thin routes compared to AAs and UAs 787s. So I don’t see India returning any time soon.