Evacuation was the process of removing civillians from an area that was deemed to be under threat.
During World War II, many British children were evacuated from major cities. In 1941, the Blitz forced many children in London to be evacuated. Tom Flanagan was taken to Cardiff and then out to the countryside. (TV: Ghost Machine)
In 1974, a chosen few UK residents were evacuated by the Prime Minister and either Brigadier Lethbridge-Stewart or General Maxwell-Lennon in the wake of an approaching galactic cyclone. (COMIC: Doomcloud)
In an alternate world, people from London and the surrounding area were evacuated after a replica of the Titanic crashed into Buckingham Palace, causing a nuclear explosion. The Noble family were evacuated to Leeds. (TV: Turn Left)
In an alternate timeline, the First Doctor and Captain Parlos organised an evacuation of Urbinia after the Daleks attacked the planet with the Time Destructor. The whole operation went badly. The Dalek Fleet intercepted every ship leaving a city and they all surrendered, leaving the capital, Kiria, effectively besieged. The Second Doctor managed to restore the original timeline. (AUDIO: Daughter of the Gods)