WWF working together China's top networking sites hijacked the digital space with 'smog' during Earth Hour to highlight China's growing air pollution hazard.

China's top networking sites - including Ren Ren, Ten Cent, Ushi and Youku - allowed a digital 'smog' to hijack their websites for an hour.

Netizens online during Earth Hour were welcomed by an unpleasant surprise - a cloudy grey smog engulfing the websites they use.

A location based tracker that tracked the users IP address pulled real time AQI index for that location

Followed by a message ‘If you wont accept smog in your digital space, why would you accept it in real life?’. To clear the smog, users had to share their smog infested page on their social networks.