T HE SCHOOLCHILDREN started to vomit. Some fell unconscious and were whisked into hospital. Angry parents demanded an explanation. The food-poisoning scandal quickly lit up Chinese social media. A kindergarten teacher in the central province of Henan was detained—accused of adding sodium nitrite, which can be toxic in large doses, to the meal boxes of at least 23 pupils late last month.

Most comments online have focused on the evil of the act and have expressed sympathy for the parents. But a surprising number have noted the alleged perpetrator’s home province. “I’m not surprised. Henan people would stoop to anything,” says one commentator on Baidu Tieba, a social-networking site. “Apart from wicked, I can’t think of another word to describe Henan people,” chimes in someone with more than 50,000 followers on Weibo, China’s version of Twitter, who identifies himself as a financial journalist.

Han Chinese are more than 90% of the population and their prejudice against ethnic minorities is well documented. In Tibet and Xinjiang it has reinforced the Communist Party’s repressive tendencies. Discrimination by Han people against members of their own ethnic group is less well-known, but also common. Its consequences are not as appalling, but it makes life tough for tens of millions of people. Over the past three decades it has been fuelled by the migration of more than 200m rural dwellers into cities, which has turned urban areas into mosaics of people from hugely varied backgrounds.

Not all men are brothers

Urban Chinese are often contemptuous of these internal migrants, wherever they are from. But people from certain regions suffer higher than usual levels of negative stereotyping. Regional discrimination “is hard to see and touch” yet its impact is as painful as getting “a bloodied face”, said an academic quoted by a north-eastern newspaper. Yang Yong, a migrant worker from Henan who lives in Beijing, has felt this. He says he was once refused a construction job in the capital because of his home province. “When I answered I’m from Henan the boss said goodbye,” he recalls. Online job advertisements for domestic maids in Beijing often specify that “applicants from Henan and the north-east need not apply.” A recent trawl through a popular website for household work, 2x9d.com, found that a fifth of such jobs explicitly excluded applicants from these two regions.

People from Henan and the north-eastern provinces of Heilongjiang, Jilin and Liaoning are among those most commonly targeted, partly because those areas are such big sources of migrants. Henan is a farming province of about 100m people. The latest census, in 2010, showed that 7.5% of Henanese were living outside their home province, the second-highest proportion of any province. The highest was Anhui, on Henan’s eastern border.

Even among better-educated urban residents, north-easterners are often stereotyped as quarrelsome and pugnacious, and Henanese are commonly regarded as thieves and cheats. In Chinese television comedy, actors playing criminals often speak with a Henan accent. The “Spring Festival Gala” of 2017, the most-watched show of the year, included such a sketch. Some regional stereotypes are harboured only by people from a particular area. In a book published in 2015, Agnieszka Joniak-Luthi of the University of Zurich says that Shanghai residents sometimes describe people from northern Jiangsu, a province that borders on the city, as “boorish” and “unkind”. However, people from that region are not so despised in Beijing. Those from Anhui are also often scorned in Shanghai, but not so much elsewhere.

Egregious examples of regional stereotyping occasionally cause outcry. Such was the case with the “Spring Festival Gala”. Online complaints from Henanese prompted the director of the show to issue a half-hearted apology. Last year a hiring manager at iQiyi, an online-video firm, instructed a subordinate (in a leaked email) to “filter out” applicants from Henan. In 2017 Meituan, an internet conglomerate best known for its food-delivery app, admitted to excluding applicants from Henan and the north-east for an open position. Both companies later apologised. After each incident, many Henanese and some sympathisers elsewhere vowed to show their displeasure by deleting the mobile app of the firm in question.

In China’s state-controlled media, diyu hei, or “regional blackening”, is occasionally condemned. In an article about the iQiyi episode a newspaper controlled by the prosecutor-general’s office quoted a lawyer as saying that such discrimination had probably occurred in tens of thousands of companies but had never come to public attention. Beijing News last year quoted Bai Yansong, a Chinese television anchor, as saying that regional discrimination was getting worse. If allowed to continue, he said, the problem could turn into “a huge cause of social instability and division”.

Some lawyers say a legal loophole is partly to blame. China’s employment law prohibits discrimination on grounds of ethnicity, sex, religion, disability, social background and health. Regional origin, however, is not mentioned. Some legal scholars and legislators have called for a wider law that would prohibit all kinds of unfair discrimination, including the region-based sort. The government, however, does not appear enthusiastic. Some conservative officials may fear such a law would also have to specify gay rights (homosexuality was only removed from an official list of mental illnesses in 2001). They may also worry about a clash with the country’s hukou system, which allows officials to discriminate openly against migrants from other parts of China in government employment and the provision of public services.

It may be that the problem of job discrimination will be alleviated by a growing shortage of migrant workers. Employers will find it harder to act on their prejudices. “In order to discriminate by region, you must first be presented with an abundance of choice,” says Huang Leping, the head of a legal-aid centre in Beijing. But region-based prejudices will long remain. In an open-air dating market in Beijing, where parents gather to try to arrange matches for their adult children, some participants admit they would not welcome a Henanese in the family.