The Chernobyl disaster was an accident at the Chernobyl Nuclear Power Plant on April 26, 1986 at 01:23 a.m., consisting of an explosion at the plant and subsequent radioactive contamination of the surrounding geographic area.
The power plant is located near Pripyat, Ukraine, at the time part of the Soviet Union.
It is regarded as the worst accident ever in the history of nuclear power.
A plume of radioactive fallout drifted over parts of the western Soviet Union, Eastern and Western Europe, Scandinavia, the UK, Ireland and eastern North America.
Large areas of Ukraine, Belarus, and Russia were badly contaminated, resulting in the evacuation and resettlement of over 336,000 people.
About 60 percent of the radioactive fallout landed in Belarus, according to official post-Soviet data.
Contamination from the Chernobyl accident was not evenly spread across the surrounding countryside, but scattered irregularly depending on weather conditions.