A combination picture shows Hong Kong’s central financial district’s Bank of China Tower, Cheung Kong Centre, HSBC headquarters, Standard Chartered Bank before and during Earth Hour

A combination picture shows Hong Kong’s central financial district’s Bank of China Tower, Cheung Kong Centre, HSBC headquarters, Standard Chartered Bank before and during Earth Hour

A combination picture shows Hong Kong’s central financial district’s (from L to R) Bank of China Tower, Cheung Kong Centre, HSBC headquarters, Standard Chartered Bank before (top) and during Earth Hour March 28, 2015. Lights go off around the world at 8.30pm local time in a show of support for renewable energy during Earth Hour, an event organised since 2007 to promote a sustainable future for the planet. REUTERS/Tyrone Siu