Swedish and Swiss researchers have measured the concentrations of four main "forever chemicals" in rainwater, and found that they are well above safe levels almost everywhere in the world, according to the BBC and the EcoWatch.

Per- and polyfluoroalkyl substances (PFAS) is a group of 4,700 artificially synthesized substances. The most famous of them is Teflon. They are used for dyeing clothing and food packaging, creation of cosmetics, and for the production of dirt and water repellent coatings.

PFAS absorbed by the body increases the risk of cancer, birth defects in babies, liver and thyroid diseases, as well as hormonal problems.

"We argue here that we're not within this safe operating space anymore because we now have these chemicals everywhere, and these safety advisories, we can't achieve them anymore," said Professor Ian Cousins, the lead author from Stockholm University.

"I'm not saying that we're all going to die of these effects. But we're in a place now where you can't live anywhere on the planet, and be sure that the environment is safe."