(Reuters) - Reliance Industries' U.S. unit has bought a 21% stake in U.S.-based helium production company Wavetech Helium for $12 million, the conglomerate said on Thursday, in a move aimed at expanding its low-carbon energy segment.

The billionaire Mukesh Ambani-run group, which operates the world's biggest oil refining complex at Jamnagar in the western Indian state of Gujarat, announced in 2021 investments worth $10 billion to develop its green energy portfolio and achieve its 2035 net zero carbon goal.

Helium gas, a by-product of mining natural gas, is used in several green technologies, as well as in medical applications, scientific research, aerospace and aeronautics, electronics, fibre optics, among others.