BEIJING – For years, the public payphone in Beijing — demurely shielded by its bulbous, yellow cover — sat underused, eclipsed by the rise of the smartphone. Then on a Saturday in July it began ringing ... and ringing ... and ringing.

It rang every Saturday for weeks with a barrage of calls, each a plea for help from residents of a community cut off from the rest of the world.

Curious pedestrians passing by answered the phone as well as volunteers. The pay phone is the star of a performance art to highlight the irony of a hotline in a city hundreds of miles away which has been ignoring cries for help from its own residents.

"The air is constantly laced with a stinging, almond-like smell. We can barely breathe freely at home. My throat aches, as if someone is grasping it," a woman named Hong Yu said on the other end of the phone one July afternoon.

Hong is among 2.71 million residents who live in a coastal city in northern China named Gourd Island, where they say they have been suffering from years of severe pollution emitted by a zinc factory and several pesticides and chemicals firms.

Despite a petition system that in theory allows any Chinese citizen to ask national leaders in Beijing for redress, Gourd Island residents say they have been stymied and harassed for years – highlighting how even the smallest social dissent in China can now be smothered by an extensive digital surveillance and online censorship apparatus.

The plight of the Gourd Islanders caught the attention of Nut Brother, a Chinese artist known for his environmental activism through absurdist performances. He's vacuumed up dust from Beijing's smoggy air and turned it into a brick, transformed a river discolored by pollution into soup by tossing in toy fish and fake red peppers, and clamped his mouth shut with a variety of devices, including a face mask that read "shut up," to protest censorship.

Nut Brother came up with the idea of using the old payphone as a hotline for pollution victims.

The idea was to use a very old-school form of communication to draw attention to Gourd Island pollution, as online petitions and blog posts documenting the city's air pollution were quickly deleted by online censors and dozens of formal complaints submitted by Hong and her neighbors to the provincial environmental bureau and municipal office were ignored.

"The local government has chosen the development of the economy at the cost of our health. We need help to get our voices heard," Hong said.

Residents began calling the yellow Beijing public payphone 265 miles away in a desperate attempt to raise attention in the country's seat of political power.

Nut Brother then pasted a poster on the phone booth, sharing a clip of it online, and called on volunteers to come and answer the phone: "Every Saturday, between 3 PM to 5 PM. Let's petition to this public payphone in Beijing rather than to call the mayor's hotline."

What's going on in Gourd Island

Originally built by a Japanese colony in the 1930s in the mineral and natural gas-rich city of Gourd Island, the zinc smelter there remains one of Asia's largest.

Nearly half of the heavy metal components discharged in sewage in Liaoning province, where the city is located, are attributable to Gourd Island, and the lead content of its air also far exceeds the permitted limit, according to Greenpeace, the environmental protection organization.

The city remains densely populated by heavy industry, with 194 factories identified by local environmental authorities as high emissions factories, according to a regulatory list published in 2022. Nearly three quarters of the factories listed are in the metals and chemicals industries.

China has tried to correct some of its environmental excesses. In recent years, it has shut down inefficient steel plants and invested heavily in state renewable energy projects, especially solar power and hydropower, though the country's power grid still struggles to transport that energy to the densest cities.

However, cities like Gourd Island, whose municipal revenue is still reliant on jobs and taxes from the chemicals sector and heavy industry, have struggled to make the shift toward stronger environmental protection.

The city remains heavily indebted, and its per capita GDP ranking, a measure of a nation's standard of living, has fallen to the bottom 25% at only about a third of the national average.

Meanwhile, current Communist Party leader Xi Jinping's regime has tightened political control, decimating a once-nascent civil society movement that had notched some notable wins for environmental protection.

Now, those who push for social change, even if their cause has little to do with politics, are increasingly detained and boxed in by digital surveillance controls that curb online speech.

Weeks after trying to share information online about air pollution, Hong Yu, the woman NPR spoke to on the public payphone, was detained by Gourd Island authorities for 24 hours. After she was released, she published a TikTok video in which she seemed under strain. The video was likely filmed under coercion.

"I made up the information in my previous videos to get likes," Hong said in the video, before apologizing for sharing false information about zinc pollution. "Actually, life is great in Gourd Island," she added.

Lessons in how to evade surveillance

Such digital and political controls have made even reaching Gourd Island residents a challenge. A small group of volunteers is working with the artist Nut Brother to film the phone booth project and amass testimonies from pollution victims without catching unwanted attention from eagle-eyed authorities.

"The biggest challenge is that the pollution victims are all using Chinese-made phones, and [these individuals] are all a bit older, so they are new to digital tools," said Li Yuchen, an encryption expert who has been helping residents circumnavigate state censors and evade surveillance using readily available open-source software tools, which are not commonly used in China and are difficult for the government to keep an eye on.

"I want the residents to be seen and to help them to be noticed by not just me, one person, but a broader audience," said Li. "As long as there's one person who learns how to use open-source software, I feel hope. I do not have a particular goal; the meaning of activism lies in practice itself," he said.

Li's efforts with Nut Brother and the residents of Gourd Island appear to have borne some fruit. Authorities in Gourd Island say they have since started an investigation into 21 factories discharging toxic gases, during which the companies must suspend operations.

However, Gourd Island residents worry that the polluting activity will resume once public attention dissipates and suspect the factories are still secretly operating at night, when regulatory scrutiny is less intense.

The environmental authorities in Gourd Island and Liaoning Province did not respond to NPR's requests for comment.

And now, someone is interfering with the residents' efforts to raise awareness. A month into the public art project, the most frequent users of their Beijing-based public payphone "hotline" became irate strangers claiming to be nearby Beijing residents. When they answered, they told the islanders: Stop calling, no one cares.

When NPR tried to call the public payphone in late September, the phone no longer rang.