Smoke rises from the Popocatepetl as it spews incandescent volcanic material on the outskirts of Puebla

Smoke rises from the Popocatepetl as it spews incandescent volcanic material on the outskirts of Puebla July 4, 2013. The 5,450-metre (17,900 ft) Popocatepetl volcano has been kept on yellow phase two alert, the second-highest warning on the center’s seven-step scale, according to local media. REUTERS/Imelda Medina (MEXICO – Tags: ENVIRONMENT TPX IMAGES OF THE DAY) – RTX11CF7