AFP / Getty Images A resident pours mud along a street outside his home in Beijing on July 26, 2012, after the worst rainstorms in six decades pounded the capital

Like mosquitoes after a rainstorm, disasters in China are inevitably followed by persistent, nagging and uncomfortable questions about how many people died. It is the same if the disaster is massive, like the 2008 Sichuan earthquake that killed 87,000, or comparatively small, like the shopping-mall fire earlier this month in the city of Tianjin that officials say killed 10. It matters not if the cause is disease, like the SARS epidemic that spread across the country and then around the globe in 2002 and 2003, or the high-speed-train collision in Wenzhou one year ago that left 40 dead. In China, where calamities have long been covered up and concealed, the doubts about death tolls run deep.

On Thursday evening, the government announced that 77 people had died in last weekend’s Beijing floods and listed the names of 61 civilians and five officials. That followed widespread questioning of the earlier death toll, which had stood at 37 since Sunday. “Why are we always playing games with statistics?” novelist Xu Kaizhen wrote on Sina Weibo. “Announcing the correct death toll is responsible and moral.” Even the People’s Daily, the mouthpiece of the Chinese Communist Party, has called for greater openness. In an editorial on Thursday titled “Death Tolls Aren’t ‘Sensitive Topics,'” the newspaper lamented that citizens are still questioning official figures. “Only when you have ‘open’ and ‘timely,’ faster-released and better quality information will you put people first and ‘desensitize’ death tolls,” it said.

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The Beijing government has pledged to be open about the figures. During a press conference late Wednesday, spokesman Pan Anjun listed several statistics, from 541 mm of rain in the hardest-hit Fangshan district to $1.8 billion in damage to 1.6 million residents affected. But he did not provide a new death toll. According to a report in the Changjiang Daily, a newspaper based in the central city of Wuhan, a reporter from CCTV, the state-run broadcaster, said she had seen the sheet from which the official was reading, and it listed a death toll of 61, but the assembled spokespeople declined to answer her question.

The Changjiang Daily story has since been removed from its website, part of extensive online censorship that has surrounded flood coverage. On microblogs, including Sina Weibo, users have complained about the disappearance of messages related to the flood. On Thursday evening, the search function on Sina Weibo appeared to be disabled, allowing users to search only for accounts, not content. Most significantly, at least four pages’ worth of flood coverage from this week’s edition of Southern Weekend, one of the country’s leading news publications, were killed by censors, according to a person familiar with the decision.

The sensitivity over disasters and death tolls has existed since the founding of the People’s Republic, says Frank Dikotter, a professor of history at the University of Hong Kong. “Communist states scrutinize any reports of unnatural death — suicide, accident, starvation — because those stand as statements of the political health of the regime as a whole,” says Dikotter, author of Mao’s Great Famine, a book that examines the deadliest episode of cover-up and faked numbers in the country’s history, the 1958–62 famine during the Great Leap Forward that killed as many as 45 million. “When it comes to unnatural ‘natural’ deaths — flooding or earthquakes — these numbers are extremely sensitive and therefore unreliable.”

Experience with scrubbed numbers has left many in China wary of official statistics, particularly when they deal with human life. During the SARS epidemic, mainland Chinese officials were slow to tell the outside world about the then mysterious disease, which helped fan its global spread. When a handful of cases arrived in Beijing, the government said they were under control, even as the disease spread rapidly through the capital’s hospitals. It was not until a single doctor spoke out that it was revealed that the total cases were several times what the government had claimed.

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After the 2008 Sichuan earthquake, there was little debate over the number of people killed. But a subset of the total, the number of children who died in collapsed schools, did become a point of heated contention. The government long refused to reveal that number, likely out of sensitivity that it would reflect poorly on officials who were in charge when the schools were built. The dissident artist Ai Weiwei helped to organize activists who compiled 5,196 individuals’ names. Nearly one year after the May 12, 2008 earthquake, the government released an official tally of 5,335 student deaths. That most likely wouldn’t have happened without pressure by volunteers, but their effort came at a heavy price. Tan Zuoren, a Sichuan writer who was compiling his own list, was sentenced to five years in prison for “inciting subversion of state power.” During a trip to Chengdu to attend his 2009 trial, Ai was assaulted by a police officer and later had to have emergency surgery for cranial bleeding.

Likewise, the Tiananmen Mothers, a group made up of people who lost family members in the 1989 massacre of protesters in Beijing, has also compiled the names of 203 victims during that crackdown. But the group has been harassed and members, including founder Ding Zilin, have been detained by police. In May one of the members, 73-year-old Ya Weilin, killed himself, stating in his suicide note that his grievances over his son’s death had never been answered. “These organizations that attempt to count the number of children who went missing in Sichuan or the number of dead in Tiananmen, they don’t receive any support,” says Dikotter. “They end up being censored at best and put in jail at the worst. It’s very difficult to find out this kind of information. It is so sensitive.”

In response to the Beijing floods, volunteers have launched their own investigation into the death toll. A spreadsheet posted online now lists the names of 26 dead and two missing. Based on reports of other dead, it cites an unconfirmed total of 42. “Officials have been very eager to release numbers in terms of how much property is damaged, but people are asking, ‘If you’re so quick to say how many animals are dead, what about the humans?'” says Dali Yang, a professor of political science at the University of Chicago. “There is some disconnect by officials in the sense they don’t want to draw too much attention to Beijing. A larger number would show Beijing in a bad light.”

Dikotter says in terms of scale, there is no comparison between recent disasters and the massive calamities in the Mao era like the Great Leap Forward and the Cultural Revolution. But despite pledges of openness, the official instinct to tightly control information remains. “This is a very well-rehearsed machine that’s been in place for some decades,” he says. “It can’t help itself. It wants to control information. That’s the default mode. Even if in some cases [the information] might not seem to be all that shocking, that’s just what it does. It’s like brushing its teeth in the morning, that’s what you do. You don’t think about it too much.”