I'm guessing you never read the Rubaiyat; even better - here's site for you http://www.persianatheist.com/ -- the name says it all. You can translate it using Chrome translator
Even on this thread we have an atheist quoting Hindu "scripture". I wonder how many times that religion has been disputed by them? -- Quite often -- didn't you know that the CPI and CPI (M) have ruled the Indian states of Kerala and West Bengal for decades? Here's another site for you with an evocative title http://indianatheists.com/
To look at things only through a western prism can be a mistake...
The "westernism" trend is not only in the west and neither is atheism only in the West. If you go as far back as the Panchtantras you see the threads of disbelieve in Indian philosophy. I don't know of any in Achaemenid Persia though.
People in Indiana who believe in GOD?