The UN's special envoy for Iraq says there's evidence that Syria has committed a war crime by attacking a rebel-held district with chlorine gas. Meantime, forces dividing Aleppo, Syria's largest city, have cut off each other's supply lines, leaving some two million residents trapped without food, water or medicine. Russia's effort to bring about a "humanitarian pause" in the fighting hasn't worked out so far. Borzou Daragahi is reporting on the action for BuzzFeed…
