Millions of people are expected to switch off their lights for Earth Hour today in a global effort to raise awareness about climate change that will even be monitored from space.
From Egypt's Tahrir Square to New York's Empire State Building, thousands of cities will turn off lights for 60 minutes from 8:30 pm local time, with switches flicked in around 150 countries and territories.
Newcomers to the Sydney-led initiative, now in its sixth year, include Libya, Iraq and the International Space Station, which will watch over the event as it rolls across the globe.
Since it began in Sydney in 2007, Earth Hour has grown to become what environmental group WWF organisers say is the world's largest demonstration of support for action on carbon pollution.
President Mahinda Rajapaksa will be the 15th world leader to commemorate earth hour today.
The president will observe this event from the presidential palace in kandy.
For further information on the commemoration of earth hour we contacted the western provincial council minister of agriculture, agrarian development, and environment Udaya Gammanpila.