SHANGHAI (BLOOMBERG) - Shortly after Shanghai went into lockdown, Mr Mark Liu volunteered to help authorities provide essential goods to millions of residents by becoming what's known as a Dabai, or "Big White".

The 33-year-old business director at a fund, who relocated to Shanghai recently from Hong Kong, hoped that signing up would allow him to get more transparent information on the Covid-19 cases in his complex.

For the most part, the Dabai work with neighbourhood committees to ensure residents get food and other essentials to keep daily life running as smoothly as possible, as well as carry out mass Covid-19 tests.

But he soon grew disillusioned by the experience. Not only did the details on Covid-19 outbreaks remain opaque after he became a Dabai, but he also saw some volunteers abuse their newfound authority to spy on neighbours or use their status to group-buy e-cigarettes - a luxury they denied to ordinary residents.

"Being a big supporter of authority and power seems to be deeply rooted in some residents' mindsets," said Mr Liu, who has been locked down in his compound since April 1. "There are not many people who question authority, or the very validity of the Covid-Zero policy."

Big White describes the brigades of police, medical workers and volunteers in white hazmat suits who have become ubiquitous throughout the pandemic. China's state media has used the term since the virus emerged in 2020 in Wuhan to soften their image: The moniker is the same as the local name for Baymax, the gentle inflatable robot in the movie "Big Hero 6".

After Shanghai went into lockdown in early April, however, Dabai have become the focus of public anger for their role as enforcers of the punishing Covid-Zero strategy. They are often seen in viral videos engaging in absurd activities such as disinfecting empty streets as well as brutal behaviour like barricading people in their homes, mauling pets and mistreating the elderly.

While China's ability to control its 1.4 billion population is second to none, and has helped limit its Covid-19 death toll to the lowest in the world, the Communist Party has always depended on grassroots soldiers that don't always stay in line.

In some extreme cases Chinese web users have referred to Dabai as "white guards" - in a nod to the Red Guard zealots of the Cultural Revolution under Mao Zedong, which led to mass killings and economic destruction that lasted for a decade until his death in 1976.

"There has always been a strong stress on collective action in China, in which individuals can have their interests subsumed by the overall needs of society," said Dr Rana Mitter, a professor of Chinese politics at Oxford University. "The Big Whites also play a convenient role for the government, as they can deflect popular anger from the central authorities."

Until the Omicron variant laid bare the weaknesses of President Xi Jinping's Covid-Zero policy, many citizens welcomed calls to sacrifice their personal needs for the greater goal of stemming the spread of the virus. Now that mindset is shifting along with the view of the Big Whites, who are increasingly seen as villains as the disconnect grows between their actions and the cute name bestowed upon them.

The most shocking behaviour perpetrated by Big Whites caught on video includes the beating to death of a corgi by volunteers in Shanghai's Pudong area after the dog's owners were taken to quarantine and forced to hand the dog to the neighbourhood committee. Chinese authorities say that animals can be vectors for the spread of coronavirus.

In another widely circulated WeChat post that has since been deleted, a woman described how Big Whites worked with police and a locksmith to break into her 94-year-old grandmother's apartment in the middle of the night to bring her to quarantine. After the woman refused to leave, they dragged her on the ground, until her son agreed to leave with them. The local neighbourhood office defended the action, saying they were worried when no one answered the door.

"Those Big Whites don't have any sense of humanity," said Mr Samuel Yu, a 40-year-old marketing executive in Shanghai who watched the videos. "But those in my compound have worked very hard since lockdown - I believe they have no choice sometimes."

One Big White in Shanghai, who asked not to be identified due to fears of recriminations, said he signed up online for the job and was chosen by street-level authorities.

Describing the work as "very stressful", he said he needed to stand outside in an ill-fitting hazmat suit for as long as six hours at a time, meaning that he can't really drink water or go to the toilet. The volunteer said he was told not to sit unless it seemed like he was going to collapse.

Big Whites also carry out the kinds of banal tasks that highlight the futility of many Covid-Zero rules that must nevertheless be enforced with no excuses. In one viral post, a worker in protective gear was filmed following a lone man in Shanghai who defied orders and tried to take a walk outside. The worker held a microphone to the man's face and repeated "go home" on a loop.

Such behaviour underscores how many volunteers are not well-equipped to deal with outbreaks, and reinforces the image that they are merely there to carry out orders handed down from higher-ups.

Mr Liu, the volunteer in Shanghai, said the Dabai weren't even taught how to properly wear and dispose of protective gear.

Ralf, a 48-year-old German expatriate in Shanghai who asked to be identified by his first name, said talking to Dabai was like "talking to a child" because many lacked any real knowledge about Covid-19 or could explain in a meaningful way the rules associated with Covid-Zero policies.

"If you accept the system - of the need for them to control us like the secret police - as being good for you and for the city, then these people are doing a tremendous job," he said. "But they are prison guards."