It's always difficult to compare cross countries: for instance it's prettty usual for bigger companies in the US/EU to outsource whole areas that are low paying with high turn over to avoid dealing with the HR. Facebook is famous for outsourcing content moderation, but I'd expect QA and other lower pay "engineering" jobs to be outsourcedas well.

If Indian companies have incentives to keep them in-house, that simple structural difference would completley chaange the numbers.

I'm not sure we havr "facts" (numbers) that are immune to these discrepancies.