Shanghai, the host city of Expo 2010, will offer a glimpse of a greener future, Achim Steiner, Under Secretary General of the United Nations, said Tuesday.

China's green efforts were highly spoken of in the "UNEP Environmental Assessment Expo 2010 Shanghai China" which was unveiled Tuesday, 256 days before the opening of Shanghai World Expo.

"Shanghai has in the last ten years taken the Expo as a driver and taken a significant increase in efforts and progress in environmental policy and pollution," said Steiner, who also serves as the executive director of the United Nations Environment Programme (UNEP).

The experience of Shanghai in handling environmental issues provided valuable examples and lessons for other cities in China and worldwide, he added.

The assessment report covers nine areas including air quality, transportation, energy, solid waste, water and public participation.

From 1997 to 2008, Shanghai had upgraded 5,975 coal-boilers to use cleaner energy, such as natural gas, creating a "coal-free zone" of 666 square kilometers.

Between 2005 and June 2009, Shanghai installed flue gas desulphurization devices for all the coal-fired power units with a total capacity of more than 10 million kilowatts.

Meanwhile, small and insufficient coal-fired plants with a total capacity of 695,000 kilowatts had been shut down, including the Nanshi Power Plant, located inside the Expo site.

The Expo will be held from May 1 to October 31, 2010. Shanghai had an average of 63 days with "excellent" air quality during the same periods from 2006 to 2008.

In 2008, the city enjoyed 328 days of "excellent" or "good" air quality, among which 101 days had "excellent" air quality, up by 68 percent compared with five years ago.

The air quality ranking in China's mainland is based on the Air Pollution Index (API), which is decided by the level of five atmospheric pollutants, including CO, SO2, NO2, PM10 and ozone.

With an API ranging from 0-50, the air quality is considered "excellent" and 51-100, "good".

Shanghai is expected to build a 400-km subway system before the Expo opens.

Shanghai has developed one of the largest subway system in just 12 years while the same length took London 100 years, Steiner noted.

The report points out the need to tackle the nitrification of the river system and suggests that regional cooperation is the key. It also calls for a comprehensive waste reduction strategy.

This is the first time the UNEP issued an assessment report on the environmental impact of holding Expo.

"It is not only because Shanghai Expo is the biggest one so far, but also because we want to share Shanghai's good practices with the world," Steiner explained.

The report acknowledges an incremental green investment made by Shanghai since it bid for holding the event in 2000. In 2009, the city has invested 42 billion yuan ($6.15 billion), tripling that of 2000.

The green efforts will not only benefit 70 million visitors of the Expo but also leaves a green legacy to the 20 million Shanghai citizens.

A follow-up report will be issued by the UNEP after the closing of the Expo.

The UNEP had issued two environmental assessment reports concerning Beijing Olympic Games.

Source: Xinhua