When a hospital in a busy suburb of Beijing caught fire last Tuesday, news of the raging fire did not appear online until about eight hours later.

This seems impossible in the age of smartphones and social media.

But the initial blanket ban – and subsequent deletion of videos related to the fire – illustrates how China has refined its censorship apparatus, according to experts.

The Covid-19 pandemic, a deadly fire in an apartment complex in Xinjiang in November 2022 and the subsequent protests it sparked, have given internet administrators additional opportunities to fine-tune their information controls, writes the AFP news agency.

Shortly after news of the fire in Beijing broke at 9pm last Tuesday, searches for the term “Beijing Changfeng Hospital fire” were banned on the social media platform Weibo, returning a message that results could not be found “according to relevant laws, regulations and guidelines’.

When videos of the fire began to appear on Tuesday, they were removed within minutes, only to be replaced by new posts. This became a game of cat and mouse between netizens and moderators that continued throughout the night.

Searches on other sites such as Baidu and Sohu brought up many results, but closer examination showed that all of these were state-affiliated or state-aligned media reporting in line with the government’s narrative.

Comments that the authorities’ information could not be trusted, as they had tried to keep the fire under wraps for hours, were also deleted.

The censorship on search platforms, including social media platforms such as Weibo and Douyin, seem to be moving in the direction of selectively showing results from authorized sources rather than blocking all results for a search.So the censorship seems less obvious, says Jeffrey Knockel, senior researcher specializing in censorship at The Citizen Lab at the University of Toronto Munk School of Global Affairs and Public Policy.

Although the fire, which has claimed 29 lives so far, was the biggest news of the day, netizens noted that it never became a trending topic on Weibo.

Beijing has put the onus on tech companies to ensure that only “appropriate content” is allowed on their platforms, with violations of the “regulations” being punishable by heavy fines.

Since 2022, websites and social media platforms have also been responsible for reviewing comments before they are published, to ensure there is no “offensive” content.

At a popular social media and e-commerce platform with hundreds of millions of active users each month, thousands of moderators review content flagged by the algorithm, said a government official who did not want to be named.

Sometimes there are instructions in the form of a list of “forbidden words”, depending instructions at the time, but for the most part it is the companies themselves who have to find out what is allowed and what is not, she said.