Over 30 cities in Indonesia, a vast archipelago country, will join in Earth Hour 2013 on Saturday (March 23) at 8:30 pm, as the world\'s largest environmental movement to help save the planet, Antara news wire quoting official said here on Friday.\"Thanks to the increasing public campaigns particularly on the social network, Earth Hour has been able to attract more Indonesian cities to participate in the movement promoting a change of life style,\" WWF Indonesia\'s Climate and Energy Program Director Nyoman Iswarayoga, said here.The NGO has been campaigning Earth Hour in Jakarta since 2009. In 2012, Earth Hour was considered the world\'s largest environmental campaign which was participated in by two billion people in 7,001 cities in 152 countries.This year, 14 mayors and district heads as well as 5 governors across Indonesia have been committed to joining Earth Hour.The huge participation indicates the success of Earth Hour campaign in Indonesia, said Nyoman.The country\'s capital of Jakarta has taken part in Earth Hour since 2009 as a movement to make Jakarta greener, he stated.As in the previous years, Earth Hour in Jakarta will be celebrated by turning off the lights in several iconic buildings such as the Jakarta Governor\'s office, the National Monument ( Monas), the Hotel Indonesia (HI) Circle, the Arjuna Wiwaha fountain, and the Youth Statue.The lights along main boulevards such as Sudirman, Thamrin, Gatot Subroto and Rasuna Said streets, will also be turned off.Earth Hour is a worldwide event held towards the end of March every year, encouraging households and businesses to turn off their non-essential lights for one hour to raise awareness about the need to take action on global warming.