‘Rats everywhere’: numbers caught are up 323%. So why are authorities not worried?

Hygiene department says rising numbers over past decade show trapping works, but experts caution residents’ daily lives may give opposite impression Illustration: Lau Ka-kuen Hong Kong resident Yau Suk-ming was startled in her kitchen when her daughter turned on a countertop blender and a rat leapt out into the open. The rodent scurried away before the 74-year-old retiree could catch it, but she was not surprised as she had earlier noticed rat droppings in her flat on Kowloon City’s Bulkeley Street. “Turns out rats are afraid of ‘earthquakes’ – but I was not afraid, I am very proud of that,” she joked, saying she could not do much but put up with them. Yau may be sanguine about her pest problem, but the rats lurking in the underbelly of the city’s wet markets, butcher shops and fresh produce stores have increasingly become a cause for wider concern about public health and hygiene. The number of live or dead rodents caught and collected every year has risen by 323 per cent in the past decade, but authorities said their containment strategy, assisted by AI, was working. That message, however, could contradict what residents saw in their daily lives, experts said. “A high rodent absence rate gives the impression that Hong Kong is almost rodent-free in certain districts, yet some residents have reported that the rat infestation problem is getting worse,” said Brian Wong Shui-hung, a researcher at local think tank Liber Research Community. “It is important to communicate the severity of the rodent situation effectively to the public, to enable people to understand the extent of the problem, track changes and act accordingly if needed.” Tracking rats with AI The Food and Environmental Hygiene Department (FEHD) said it had deployed the latest artificial intelligence technology to track and capture rodents. Thermal imaging cameras installed across Hong Kong take images at two-minute intervals from 7pm to 7am for three consecutive nights, every six months. Unhandled type: inline-plus-widget {"type":"inline-plus-widget"} The system’s AI algorithm detected and counted rats from their thermal signatures, analysed the frequency of their appearance and peak activity hours, and mapped dispersal routes, a spokesman told the South China Morning Post. This provided the absence rate, which was measured by dividing the number of snapshots in which no rodents were detected by the total number of images taken. According to department statistics, the rate exceeded 90 per cent across all 18 districts in the second half of last year. Eastern, Islands and Tuen Mun districts were more than 98 per cent rat-free, while Sai Kung topped the list at 99.5 per cent. Wan Chai and Kowloon City were the only two districts with more than 10 locations recording a rat absence rate below 80 per cent. A rat foraging beside a rubbish bin at a park in Jordan. One public health expert pointed to Tokyo’s approach to curbing infestations, including strong hygiene practices among the population, proper food waste categorisation and recycling. Photo: Jelly Tse To ensure dynamic surveillance that responded to new rat hotspots, the placement of the thermal cameras was “continuously calibrated” based on verified complaints, live and dead rodent catch figures, routine inspections and views of local communities, the spokesman said. The number of live or dead rodents caught or collected in Hong Kong in the first half of 2026 stood at 87,105. The annual number had risen in the past decade, from 37,169 in 2016 to 157,182 in 2025 – a 323 per cent increase. The number of rodent complaints had hovered at around 10,000 to 11,000 annually over the past decade. But the number received by the FEHD from January to June this year jumped by 33 per cent year on year to 6,463 – the highest in the past four years. The rise in live rodents caught indicated an “improved operational efficiency” rather than evidence of a growing rodent population, the FEHD spokesman said, adding that the relatively stable number of complaints showed “no evidence of a territory-wide surge in rodent infestation”. Does tracking work? In June, authorities cracked down on the Kwun Tong branch of a popular butcher shop, Qiandama, after a video showing rats running over pig carcasses on the premises went viral online. It was followed soon after by another viral video showing rats scurrying around Taste supermarket in Festival Walk shopping centre in Kowloon Tong. A few months earlier, a rat was spotted in a sushi chiller at a Don Don Donki outlet in Tuen Mun. “The rat problem in Hong Kong is so bad this year,” one user said on the social media site Threads. “Once it gets dark, you easily see a dozen rats in a single alleyway in the older districts.” As more rodent sightings were shared online, questions arose about the accuracy of the thermal camera system as an indicator of Hong Kong’s rodent problem. Wong from Liber Research Community said that while the absence rate was a “robust metric” to gauge rodent activity, it was ineffective as a means of communicating policy to the general public, whose experiences could contradict the positive figures. Echoing this sentiment, Ming Wai-kit, an associate professor at City University’s department of infectious disease and public health, said: “While the rate provided by the government looks good, the reality is that the public’s perception is different. They actually see rats walking past them.” Michael H Parsons, an urban ecologist and senior research scientist at the Centre for Urban Ecological Solutions in Texas, who has studied rodent issues in Singapore and Tokyo, noted that a high rodent absence rate did not mean Hong Kong was rodent-free. Trapping cages in an alleyway behind 8 Ma Tau Wai Road in Hung Hom. District councillor Lam Tak-shing noted the Highways Department had repaired broken concrete and sewage pipes in the area in an attempt to restrict the movement of rodents. Photo: Edmond So It could simply mean the rats had shifted to other locations that were not under surveillance, he said. One way to gauge the scale of a rodent problem was to measure sightings in the daytime over a few days, Parsons said. “Daytime activity indicates extremely high population pressure … persistent daytime sightings [of rodents] would suggest an overgrown rodent population, regardless of what the rodent absence rate percentage suggests,” he said. Ming, the City University epidemiologist, said global cities such as Toronto, New York, London, Paris and Amsterdam experienced rodent problems because of their high urban density, levels of food waste and ageing drainage facilities. Thermal imaging cameras used to track rat numbers and movement. Photo: Handout These cities tackled rodent problems by ensuring that water sources were clean, sealing off abandoned buildings and drainage channels where rats were located, and implementing surveillance measures and traps, he said. Ming cited Tokyo’s approach to curbing rat infestations, including strong hygiene practices among the population, proper food waste categorisation and recycling. To control rat levels in Hong Kong, authorities had to address illegal dumping and ensure food waste was handled properly, Ming said. “Hong Kong’s rat problem is not very severe [compared with overseas cities] ... but certain areas or districts have more serious rodent infestations as they are located close to markets, housing estates and eateries,” he said. Ming suggested that the government create an online reporting system so residents could register rat sightings and help the government measure and contain their prevalence. According to FEHD data, the department caught 20,215 rodents in Yau Tsim Mong last year, up by nearly 39 per cent from 2024, and the highest number among the city’s 18 districts. The increase was 26.4 per cent in Wong Tai Sin, 67.5 per cent in Sham Shui Po and 83.5 per cent in Kowloon City. Kowloon City also registered 776 complaints in the first half of this year,