Industrial upgrading remains a big challenge for Dongguan, dubbed one of the world's leading manufacturing centers, as the southern Chinese city has witnessed slower economic growth in the last three years amid the global economic downturn, the city's mayor said.

Yuan Baocheng, mayor of Dongguan, said the city has set a GDP growth target of only 7 percent this year, given that it still faces major pressure in industrial upgrading.

"It is more like climbing a mountain. We have started upgrading industries since the global financial crisis in 2008, but there is still a long way to reach the top of the mountain," Yuan said during the annual session of the National People's Congress.