The Vietnamese localities will join other cities and regions throughout the world in switching their lights off from 8:30 to 9:30 pm on March 27.

Besides Vietnam, the worldwide call for energy saving has received responses from 91 other countries, compared to 88 countries in 2009.

Earth Hour is an opportunity for the global community to speak in one voice on the issue of climate change through switching lights off, said Julianne Becker, Communications Manager for WWF Vietnam.

2009 was the first year Vietnam joined Earth Hour with the participation of six cities and provinces, including Hanoi, Ho Chi Minh City, Can Tho, Hoi An, Hue and Khanh Hoa.

According to WWF, Vietnam saved about 140,000 kWh of electricity thanks to 2009 Earth Hour.