In the lofty heights of the Himalayas, where clouds drift over snow-capped peaks, a dangerous secret is being carried on the wind. A new scientific study has found that clouds—once believed to offer the purest drinking water—are silently ferrying toxic heavy metals from polluted lowlands to some of Earth’s highest, most fragile ecosystems.

The findings not only shatter the myth of “clean” mountain rain but also ring alarm bells for human health, with potential risks ranging from cancer to developmental disorders.

Metals in the cloud is a matter of growing concern due to its adverse impact on human health on a wider scale through continental long-range transport. However, information regarding metal contamination of low-level clouds, particularly the late summer and early monsoon clouds in India is lacking.