Closures are imposed by the Israeli army by and large on Palestinians in order to restrict movement in the Occupied Palestinian Territories and Israel. These restrictions include physical structures such as military checkpoints, and Israeli-enforced orders such as closed military zones and curfews. Israel claims that closures are necessary to prevent attacks against Israeli citizens, while Palestinians point to the illegality and discrimination of such closures and their damaging effect on normal life and movement. See Checkpoints, Closed Military Zone and Curfews.  http://www.justvision.org/glossary/closures