A riot police vehicle releases tear gas on demonstrators during a student rally against the government's public education system in Santiago city Sept 22, 2011. The students are demanding for free and better state education, as well as for an end to profit-making in the public education system. [Photo/Agencies]

A riot police vehicle releases tear gas at demonstrators during a student rally against the government's public education system in Santiago city Sept 22, 2011. [Photo/Agencies]