China has begun deleting the documentary about smog that became an overnight sensation, notching up hundreds of millions of views.

Under The Dome took the country by storm with its vivid depiction of air pollution and its effect on the health of the nation. Made by a former reporter for the state broadcaster, it was available across the most popular video portals for several days.

Notably, the film was even promoted in state media, helping to explain how it reached such a staggering audience: it was viewed more than 100m times in the first 24 hours, and more than 300m times at last count. Discussion on social media was widespread and the environment minister said he had texted the film-maker, Chai Jing, to praise her work.

But despite the initial tolerance and outright support from at least some in authority, on Friday the film began to vanish, disappearing from hugely popular services including Youku and TenCent even as viewers were watching.

The page on the website of the official People’s Daily that was dedicated to the documentary had also been removed.

That may suggest disagreements among those in authority over the film. It may also indicate that officials feel it has already served its purpose or are alarmed by its runaway success.

“It is probably a bit of both,” suggested Sam Geall, executive editor of China Dialogue, a bilingual site that focuses on environmental issues.

“Clearly it had been checked before release … the initial praise from the Ministry of Environmental Protection [signalled] it had apparently signed off on it.

“I think it was intended to be out there for a little while. It’s always been something they’ve been keeping an eye on and I think it was very carefully calibrated. It highlights the way this communication is supposed to work: to push a specific line at a particular time and not to galvanise a citizens’ response.

“It was calibrated as this pointed message about corruption within the energy industry and the need for new regulations … I don’t think it was ever intended to be a Silent Spring moment. You are talking about different actors [making decisions] as well.”

Zhan Jiang, journalism professor at Beijing Foreign Studies University, said he suspected two motives for taking the film down.

“Firstly, I’ve noticed a report from Taiwanese media saying that some Beijing mothers are planning to petition events during the Lianghui [the annual meetings of the National People’s Congress and Chinese People’s Political Consultative Conference, the country’s top legislature and political advisory body].

“The authority won’t mind people discussing the problem, but if the discussion turns into action it would upset them. Plus, when foreign media report the documentary and the public discussion, it becomes an incident.

“Secondly, the authorities might be worrying that the discussion of the documentary overshadow the annual conferences.” The conferences, held annually in the spring, started this week.

Figures in the energy sector had complained about aspects of the documentary.

Some also wonder if today’s move is an attempt to reduce attention before the ministry of environmental protection hosts a press conference on Saturday.

This week the central propaganda department ordered media not to report on the documentary, tamping down attention without attempting to suppress the film at that stage.

The Financial Times said an employee at a Shanghai newspaper had been suspended on suspicion of leaking that directive.

Propaganda orders are highly sensitive and are not supposed to be disclosed.