Scientists and officials stressed the importance of innovation in urban development at the Shanghai World Expo's third forum that began in Wuxi, east China's Jiangsu province, on June 20 to 21.

"Scientific and technological innovation has become the leading force in economic and social development," said Wan Gang, minister of science and technology. "As an important carrier, the city is a main gathering place of creative elements."

Urban expansion has also brought increasing use of fossil fuels over the past 200 years, giving rise to pollution, energy shortages and global climate change, Wan said.