"The first waves of refugees began leaving Syria amid a government crackdown on
street protests. Anti-government demonstrations began in March in the southern city
of Deraa following the arrest and torture of a group of teenagers who painted
revolutionary slogans on a wall. By July, hundreds of thousands were taking to the
streets. Government forces responded with large-scale military operations...
The beginning of 2013 saw growing numbers of people flee. Deraa, Homs, Aleppo
and Damascus saw most leave. Government forces, boosted by fighters from the
Lebanese Shia Islamist movement Hezbollah and Iraqi Shia militias, recaptured key
areas and reports emerged that chemical weapons had been used."