That's really interesting. I did not know that India used commas for numbers like that, 3 digits and then 2 digits, and then apparently 2 digits again?

3,00,00,000 instead of 30,000,000

It’s the lakh and crore system [https://en.wikipedia.org/wiki/Indian_numbering_system].

Older than western civilization probably, but does take some getting used too.

I am a European, so may be wrong, but it is my understanding that Indians have intuition around lakhs (100k) instead of thousands/millions. Apparently 100 lakhs is a crore (10M), but I haven’t seen that used so don’t know how prevalent it is - lakh is very commonly used though.

https://en.wikipedia.org/wiki/Indian_numbering_system

You are correct on all counts.

It was extremely difficult to get used to when I was visiting India for a few months years ago: https://en.wikipedia.org/wiki/Indian_numbering_system