There fore it can be safely said that Slavery is still continuing from history. It never stopped even after Islam. All these expatriates are actually slaves, with no passport to return home on free will. They can not even change employment with out owner's authority ( Kifala). What else could be slavery. Even women slave are imported from third word and far east as maids.
I saw a documentary on bbc, in which they showed pathetic conditions of workers in Dubai. Ten or more slaves living in one room, sleeping on floor in shifts. The king was made aware of it, but he couldn't do any thing about it. He knows his men ( Kafeel).
Over population, poverty and corrupt governments of the third world are making their own citizen live like slaves in Mid East.