Participants in costume dance during a parade commemorating Earth Day in downtown Santiago, April 22, 2013. Students and environmental interest organisations participated in the parade, themed "March for the Protection of Water". Earth Day is an annual event celebrated on April 22, which aims to promote public awareness and protection of the environment. [Photo/Agencies]

Participants attend a parade commemorating Earth Day in downtown Santiago, April 22, 2013. Students and environmental interest organisations participated in the parade, themed "March for the Protection of Water". [Photo/Agencies]

Schoolchildren collect rubbish from Karachi's Clifton beach early morning April 22, 2013, during a cleaning campaign as part of the commemoration of Earth Day. [Photo/Agencies]