text: Earth Hour spreads | News24
  Navajo Generating Station, from Lake Powell, in Page, Arizona. (Ross D Franklin, AP)
  Last year the campaign spurred a 120 000-strong petition in Russia that galvanised parliament to pass a law protecting the seas from oil pollution.
  The countries involved last year included Singapore, Sweden, Hong Kong and the US. This year's participating countries include Australia, Britain and South Korea, with celebrities expected to make pledges.
  Singapore-based Earth Hour's headline campaign is an annual lights-out activity to underscore energy conservation. It was observed in 7 000 cities and towns in 152 countries and territories last year, the group said.
  This year's Earth Hour is scheduled for 23 March at 20:30 in participating locations.
  In SA, the WWF said that the switch off would be used to focus on the kinds of fuel used to generate power.
  "We must become aware of the kind of energy we use every day and the need to switch over to clean, renewable energy sources such as sun, wind and water," said WWF-SA CEO, Dr Morné du Plessis.