Earth Hour

The worldwide movement Earth Hour started in 2007 in Sydney, Australia as a lights-off event. In 2013 it was held in more than 7000 cities and towns worldwide.
worldwide weltweit
movement die Bewegung
lights-off Licht aus

Earth Hour is scheduled for today from 8:30 p.m. to 9:30 p.m. during participants' local time.
to be scheduled geplant sein 
sth. is scheduled (einen Termin für) etw. festgelegt haben, etw. ist vorgesehen 
participant der Teilnehmer
local time die Ortszeit

Earth Hour 2014   Earth Hour 2014