It's from 2022, so probably outdated.

> According to the US Department of Energy (DOE), about 12% of all silicon metal produced worldwide (also known as “metallurgical-grade silicon” or MGS) is turned into polysilicon for solar panel production. China produces about 70% of the world’s MGS and 77% of the world’s polysilicon. Converting silicon to polysilicon requires very high temperatures, and in China it’s coal that largely fuels these plants. Xinjiang—a region in China of abundant coal and low electricity prices—produces 45% of the world’s polysilicon.

> Reports indicate that some Xinjiang polysilicon plants have employed forced labor of Uyghurs, an intensely persecuted Muslim ethnic minority.

[0] https://blog.ucs.org/charlie-hoffs/mining-raw-materials-for-...