Munich mayor Christian Ude, arguably the most popular politician in Germany, said during his visit to the Expo on Thursday that economic growth and quality of life are equally important to make a city perfect.

"The idea is to never lose the balance of the city," said Ude, who has been the mayor of Munich for 17 years. "You need both economic power and quality of life."

A successful city also needs a mixture of industries, Ude added.

For instance, Munich, the third-largest city in Germany after Berlin and Hamburg, has a diversified industrial base, including IT, tourism, automotive, media, health and science as resilient economic engines.

Although Shanghai, with a permanent population of 17 million, is quite different from Munich, which has a population of about 1.4 million, the two cities can still learn from each other in areas such as urban road traffic, he said.

Ude was in Shanghai along with his wife, Edith von Welser-Ude, to visit the Expo and to promote a new book on his life story.

Entitled Unraveling Munich's Secrets - Dialogue between the Udes and Xiao Hui Wang was written by Wang, a photographer and film-maker.

Ude, who has worked as a journalist and a lawyer, has diverse interests in the fields of culture, writing and publishing, while his wife is a Munich city councilor, a specialist in housing, city planning and an environmentalist.

Commenting on Expo 2010 Shanghai, the 63-year-old mayor said the event is another sign of China's growing global clout following the 2008 Beijing Olympics.

The six-month fair is set to be one the largest gatherings in history, with 189 countries participating in the event. Organizers are also expecting it to surpass milestones set by previous World Expos, such as the 1893 Columbia Expo, which introduced the Ferris wheel.

Ude said the Expo's slogan, "Better City, Better Life", is "the best ever", as the urban population is continuing to soar worldwide and the international community is exploring urban strategies and sustainable development.

In 2007, more than half of the world's population lived in urban areas. By 2050, that figure will rise to 70 percent.