Vietnam saved 500,000 kWh during the Earth Hour Saturday night, with Ho Chi Minh City alone saving 67,000 kWh, according to the National Center for Power System Coordination.
The center released the figures after organizations, businesses and households in Hanoi, HCMC and more than 20 cities and provinces across the country switched their lights off for an hour from 8:30 p.m onwards.
Since the event was observed during peak hours in Vietnam, the impact in terms of power savings was remarkable, the center said.
Hanoi had displayed banners reading "Small act for big change" days before the Earth Hour day.
The city People's Committee asked the Hanoi Power Company to switch off lights at several popular sites and monuments like the area around the Hoan Kiem and West lakes, the Hanoi Opera House, billboards on main streets, 29 district offices and some other public places.
In 2009, Vietnam saved 140,000 kWh as six cities Hanoi, HCMC, Can Tho, Hoi An, Hue and Khanh Hoa participated in the Earth Hour event.
Earth Hour, held on the last Saturday of March, was initiated by the World Wildlife Fund to increase climate change awareness and induce mitigating responses. The first Earth Hour was held in Sydney in 2007. In 2009, it was joined by around one billion people from 4,013 cities in 88 countries and territories.