They will pay whatever the advertisers pay. Certain categories in certain countries can be extremely valuable, and other categories in other countries can be much less.

India, being a poor country, certainly will generate much less revenue than a country like US in the same category because the advertisers will be willing to pay much less per click.

Very much so. Can't speak of India specifically but in my experience with adsense, some of the countries with a similar to India gdp per capita often pay out 50 to 70 _times_ less than the US rates.