As the world's top producer of energy-efficient light bulbs and a potentially massive market for them, China is seen as pivotal to greater worldwide acceptance of environmentally-friendly lighting.

While also the largest producer of less-efficient incandescent bulbs, China is moving with the times as the classic light bulb, which produces more heat than light, is slowly being switched off. Developed countries have already begun phasing them out and China, the world's top source of the carbon dioxide emissions blamed for climate change, is expected to follow, with potentially huge ramifications on emissions.

"Lighting accounts for about 12 per cent of total electricity consumption" in China, and the country's biggest source of CO2 is power generation, said Li Ang, a climate and energy campaigner with Greenpeace China.

"China has been under big pressure to cut emissions and changing light bulbs could be a good way."

China's output of energy-efficient bulbs surged 12-fold in a decade - it produced 2.4 billion in 2006 compared to 200 million in 1997, according to China's commerce ministry.