China, the world's largest emitter of greenhouse gases, aims to initiate the first "green" World Expo in Shanghai, as the sprawling metropolis tries to shed its polluted past and become eco-friendly.

Solar power, recycled rainwater, hybrid engine buses -- organizers and countries participating in the six-month event, expected to draw up to 100 million visitors, are sparing no effort to create a "Better City, Better Life".

"Green thinking, protecting the environment, harmony, low carbon -- these are ideas that not only will we display at Expo, but we need to make each visitor feel them", said Shanghai Mayor Han Zheng.

China strives to significantly reduce its carbon dioxide emissions with the help of measures taken, said Xu.

The measures include establishment of Several Expo pavilions to harness the sun's rays.

Authorities have extended a warning that factories in the Yangtze River Delta up to 300 kilometers (186 miles) away could be shuttered if on-site air quality is sub-par, with a view to pose an official willingness to make the environment a priority.

For carbon reduced emission in transportation, buses are being equipped with hybrid engines, and a Chinese electric bicycle manufacturer has donated 100 electric cars and 300 electric bikes for Expo staff.