BEIJING » "Under the Dome," a searing documentary about China’s catastrophic air pollution, had hundreds of millions of views on Chinese websites within days of its release one week ago. The country’s new environment minister compared it to "Silent Spring," the landmark 1962 book that energized the environmental movement in the United States. Domestic and foreign journalists clamored to interview the filmmaker, a famous former television reporter, though she remained silent.

Then on Friday afternoon, the momentum over the video came to an abrupt halt, as major Chinese video websites deleted it under orders from the Communist Party’s central propaganda department.

The startling phenomenon of the video, the national debate it set off and the official attempts to quash it reflect the deep political sensitivities in the struggle within the Chinese bureaucracy to reverse China’s environmental degradation, among the worst in the world. The drama over the video has ignited speculation over which political groups were its supporters and which sought to kill it, and whether party leaders will tolerate the civic conversation and grass-roots activism that in other countries have been necessary to curbing rampant pollution.

"It’s been spirited away by gremlins," said Zhan Jiang, a professor of journalism and media studies in Beijing.

The video was made by Chai Jing, a former investigative reporter for China Central Television, with help from other former employees of the state network. It appears obvious that Chai had the cooperation of pro-environment officials in the party and government, according to interviews with state media employees and material in the documentary and on supporting websites. After the video’s release, other officials, including some at state-owned enterprises that often bridle at stricter environmental regulations, came out strongly against the film. The battle lines reflected those in the broader conflict over the environment in China.

The 104-minute documentary, whose title is a reference to the grim smog that pervades daily life in many Chinese cities, had become the hottest topic of conversation among many Chinese. But by Friday evening, people in China who wanted to view it on the websites of major Internet companies like Youku and Tencent found only dead links. The website of People’s Daily, the official party newspaper, had initially promoted the video and posted an interview with Chai, but those had been deleted by Friday morning.

The censors’ guillotine fell a day after the start of the annual session of the National People’s Congress, the party-controlled legislature that is supposed to represent official candor and accountability.

In recent years, there has been fast-growing anxiety among middle-class Chinese over fatal, widespread pollution of the air, water and soil resulting from a lack of environmental regulations governing industries. Chai’s self-financed documentary touched nerves in part because she voiced those concerns in a straightforward manner, from the perspective of an average citizen. The video had the polished format of a PowerPoint presentation or TED Talk, with Chai presenting sobering scientific facts to an audience from a stage while dressed simply in a white blouse and jeans. Chai, 39, hooked viewers, too, by talking candidly about her fears of the threats posed by air pollution to her infant daughter’s health — a common concern among Chinese parents.

Chai tackled the politics of environmental regulation in the video by showing how little power officials at the Ministry of Environmental Protection have to enforce anti-pollution laws. As portrayed in the film, their nemeses are large state-owned enterprises and some private companies, among them oil and gas businesses, steel producers and automakers.

The film includes interviews with officials from the Ministry of Environmental Protection talking about their inability to regulate those companies. Last Sunday, the new environment minister, Chen Jining, compared the video to Rachel Carson’s "Silent Spring" in an inaugural news conference with Chinese reporters in Beijing.

"I think this work has an important role in promoting public awareness of environmental health issues, so I’m particularly pleased about this event," Chen said, according to Chinese news reports.

Though Chai had help from that ministry’s officials in the making of her film and appeared to empathize with their plight, she knew there were political red lines, friends and advisers of hers have said. In the final cut, she avoided broad criticisms of China’s political system. An investigative journalist and friend of Chai, Yuan Ling, said by telephone that a longer version of the film had a section in which Chai argued that the air pollution was a result of China’s political system and development model, and that China would have to change these to heal the environment.

"This part of the film was unbearably heavy, dark and despairing," Yuan said. Chai decided to cut it.

In the interview on the People’s Daily website, now deleted, Chai said she sent some of her interview material to official groups, including the legal committee of the National People’s Congress and a government team working on changing the oil and gas industries. She received feedback from both groups, she said.

Despite such official support, attempts to stifle or criticize the video grew after its release, as officials grappled with its surging popularity.

Early this week, propaganda officials issued a directive telling Chinese news organizations not to report on the film and ordered video websites not to play it on their home pages, though those sites could keep it online. Editors at Global Times, a populist newspaper under the management of People’s Daily, had to kill articles and opinion pieces that separately criticized and supported Chai’s documentary, newspaper employees said.

Some officials of state-owned enterprises vented their fury. One senior oil company official, Wan Zhanxiang, wrote an essay for Cubeoil.com that attacked Chai’s arguments.

"Maybe she doesn’t have enough brains and not enough knowledge or thoughts," he wrote. "Anyway, she has no insights."

Some critics said online that Chai had received foreign financing for her documentary, even though she had said in the People’s Daily interview that she had spent about $160,000 of her own money to make the film. The money came from earnings from her books, she said.

The uproar over the documentary occurred at a politically sensitive time — during the opening week of this year’s meeting of the National People’s Congress, when party and government officials gather in Beijing to discuss broad policy matters. There has been speculation online that Chai’s documentary and the timing of its release were part of an effort by the Ministry of Environmental Protection to push party leaders this week to support greater regulatory powers against state-owned enterprises and other companies.

Yuan, Chai’s friend, called that a "conspiracy theory" and said such a move would have been "too risky for the ministry."

After a week of passionate public discourse over the film, the central propaganda department told websites Friday to remove "Under the Dome." Zhan, the journalism and media studies professor, said officials had waited through the week "to see what would happen, in sort of an opportunistic strategy."

Those in China who wanted to view the film on Friday afternoon had to search for it in obscure corners of the Chinese Internet or go to sites like YouTube, which is blocked here but is accessible with work-around software.

On Friday evening, Xinhua, the state news agency, posted on Twitter, which is also blocked here, that "President Xi Jinping vows to punish, with an iron hand, any violators who destroy ecology or environment, with no exceptions." That night, the U.S. Embassy air monitor in Beijing rated the air "hazardous."

Edward Wong, New York Times

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