Every so often, grassroots activism succeeds in China.

We saw one this week.

Caving in to public pressure, government officials in the southwestern city of Shifang in Sichuan Province abandoned plans to build a billion-dollar chemical plant.

This came just days after thousands of angry residents took to the streets in protest at the city's bid to build the $1.6 billion Molybdrenum plant.

City officials said it had passed all environmental evaluations, but local residents, worried about long-term pollution and health hazards, said "no."

Defying government and police orders, they marched to the chant of "Protect Shifang's environment, return our beautiful home!"

Soon enough, the mayor conceded and promised to suspend construction. Then on Friday, the city's Communist Party chief was sacked.

"The people have achieved their goals if their protest was just a NIMBY (not in my backyard) movement," the Global Times noted rather acerbically.

But some political observers see beyond parochial backyards.

"It is a stunning case of a local NIMBY movement coalescing with the support of nationwide public opinion through the internet," said Xiao Qiang, a U.S.-based expert on the Chinese internet.

"The new media, particularly through (Twitter-like) Weibo and popular forums such as Kaidi.net played an absolutely critical role in the whole process."

Xiao said netizens spread the news instantly and widely, exposed police violence against protesters and generated popular outrage.

"With such national exposure and public opinion on the protesters' side, the local authorities had no choice but to cave in instantly," he said.

A few other NIMBY protesters have succeeded in China.

In 2009, local residents rallied and aborted a government plan to build a waste incinerator plant in a suburban town in southern Guangzhou city.

That same year, Shanghai residents foiled a city plan to construct a high-speed train line using magnetic levitation technology complete with a raised concrete track.

Last August, thousands of protesters forced officials in the northeastern port city of Dalian to shut down and promise to relocate a controversial chemical plant that produced paraxylene (PX), which residents feared was carcinogenic.

Political observers attribute these successes to smart tactics.

"The environment is a perfect issue for the public to exploit the central-local divide," said Wenfang Tang, a political science professor at the University of Iowa in the U.S.

"People know when to claim their right to resist the local government by using central government regulations," Tang explained.

"Beijing is often sympathetic to such public demand since it does not hurt its own legitimacy. Scholars describe this tactic as the 'rightful resistance.'"

This is best exemplified by one of the Shifang protesters' banners: "Long live the Communist Party, kick out the copper factory!"

But China has been grappling with a spike in social unrest.

Anger has been rising over land seizures, a growing wealth divide, official corruption and environmental pollution.

Rural unrest is also a problem, though nothing new.