Actor Abhishek Bachchan has urged Indians to switch off lights for one hour on March 27 as part of World Wide Fund for Nature’s (WWF) Earth Hour 2010 campaign. Earth Hour is a concept initiated by WWF and is observed across the major cities of the world on the last Saturday of March annually to pledge support for protecting the environment and action on climate change. Bachchan, who has been appointed brand ambassador of the initiative in India, has pledged his support and requested the entire film fraternity to follow suit.