Art historian E.B. Havells believed that the dome was already known to Indians in BCE. He Cites Bharhut Stupa as an Example

Source:- Subhash Kak / Twitter.

A panel from Bharhut stupa depicting temple with arched gateway and hemispherical dome, 2nd century BCE. Art historian E.B. Havells believed that the dome was already known to Indians in BCE. pic.twitter.com/ZzvG54c4tv

— Subhash Kak (@subhashkak1) December 25, 2017