You can not compare two currencies without including the parities. In terms of the US dollar, India has a Purchasing Power Parity of 21.276 as of 2019 [0].
> Purchasing power parities (PPPs) are the rates of currency conversion that try to equalise the purchasing power of different currencies, by eliminating the differences in price levels between countries. The basket of goods and services priced is a sample of all those that are part of final expenditures: final consumption of households and government, fixed capital formation, and net exports. This indicator is measured in terms of national currency per US dollar
It works best when comparing people with relatively similar consumption, e.g. asking about the material lives of engineers in east- vs. west-germany. Both had cars, radios, apartments with indoor plumbing, and awful haircuts, but they paid for them with different money. Any exchange rate was basically a fiction, but even if the currencies had been freely traded, these two still couldn't buy each other's goods.
Some people in India have lives similarly comparable to the west, e.g. the class who buy iphones. But the ones who make this super-cheap data interesting really don't. I mean there are riots when the price of onions doubles after a poor harvest. It's difficult to imagine a shared basket of goods which meaningfully captures the comparison here --- between prices experienced by those whose weekly budget can flattened by onions, and people in the US.
Probably a better comparison would simply be to quote daily wages alongside such prices. GDP is about US$5/day, compared to about $175/day in the US.
It's fine to take another normalisation metric - no metric is perfect. The point was that there is a normalisation needed. Far too often I see a comment which states, "Oh! It is just 1$ so cheap!". I chose PPP because it is meant for making parities. So, 9cents may or may not be cheap. We don't know until we use a normalisation factor.
People talk about dog-years too, but past some very crude level there's no avoiding knowing something about about the lives of dogs, or parrots, or goldfish. At which point it's less confusing to use ordinary earth-years for everyone.
First, PPP has its own issues [1] and is probably not the best way to compare the price of data.
Second, even after taking PPP into account data is still much cheaper in India - 30 USD per month for the thread parent after PPP conversion.
Math below:
PPP in [2] is National currency units/US dollar, i.e. INR/USD. It says that ~21.3 INR is going to buy you the same basket of goods in India that 1 USD buys you in USA.
> Purchasing power parities (PPPs) are the rates of currency conversion that try to equalise the purchasing power of different currencies, by eliminating the differences in price levels between countries. The basket of goods and services priced is a sample of all those that are part of final expenditures: final consumption of households and government, fixed capital formation, and net exports. This indicator is measured in terms of national currency per US dollar
[0] https://data.oecd.org/conversion/purchasing-power-parities-p...