I've read that atomism developed in both Greece and India, however in India they maintained the supernatural while in Greece they did not.
I've read into this topic before, as well as having mentioned this a few times on the podcast. Kanada was the first proponent of Atomism within India, and even founded his own school that would become one of the six orthodoxes of Vedic Philosophy. Here's a very brief summary of its materialism and atomism.
QuotePhysics is central to Kaṇāda’s assertion that all that is knowable is based on motion. His ascribing centrality to physics in the understanding of the universe also follows from his invariance principles. For example, he says that the atom must be spherical since it should be the same in all dimensions. He asserts that all substances are composed of four types of atoms, two of which have mass and two are massless.
...Vaisheshika school is known for its insights in naturalism. It is a form of atomism in natural philosophy. It postulated that all objects in the physical universe are reducible to paramāṇu (atoms), and one's experiences are derived from the interplay of substance (a function of atoms, their number and their spatial arrangements), quality, activity, commonness, particularity and inherence. Everything was composed of atoms, qualities emerged from aggregates of atoms, but the aggregation and nature of these atoms was predetermined by cosmic forces. Ajivika metaphysics included a theory of atoms which was later adapted in Vaiśeṣika school.
However, something that I've also kept in the back of my mind, is the Charvaka school of thought (6th - 5th Century BCE). The atheistic & hedonist school that opposed the Vedas and the spiritual culture within India, as well as Buddhism. In some of the articles I've read, they're often compared or grouped with Epicurus (barring a few differences obviously).
https://philolu.com/2019/03/14/the…cs-of-charvaka/