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The Popocatepetl volcano spews a cloud of ash and steam high into the air in Puebla May 11, 2012. Mexico last month raised the alert level for the volcano Popocatepetl, 50 miles (80 km) southeast of Mexico City, after it began pumping out red-hot fragments of rock and ash. The country has been closely monitoring the 17,900-foot (5,450-metre) volcano, which has prompted school classes in nearby villages to be suspended on days of higher activity. REUTERS/Imelda Medina