Effects of the Chernobyl disaster
The Chernobyl disaster of 26 April 1986 triggered the release of radioactive contamination into the atmosphere in the form of both particulate and gaseous radioisotopes. As of 2026, it remains the world's largest known release of radioactivity into the natural environment.
Source: Wikipedia — Effects of the Chernobyl disaster (CC BY-SA 4.0)