If you walk down a back alley in Mong Kok, Wan Chai, or Hung Hom after dusk, you're bound to see them. Large brown rats darting between grease traps, squeezing under metal gates, and chewing through plastic garbage bags. Ask Hong Kong's Food and Environmental Hygiene Department about the situation, though, and they'll offer a surprisingly upbeat view.
The government caught or collected 157,182 live and dead rodents in 2025 alone. That's up from 37,169 in 2016, marking an eye-popping 323% increase over a single decade. In the first half of 2026, authorities picked up another 87,105 rodents.
Officials see these figures as proof that their traps and night-vision tracking systems are working. Residents and pest control experts see the exact opposite. When catch numbers shatter records year after year, it doesn't mean the streets are getting cleaner. It means the underlying population is exploding.
The Math Behind Hong Kong's Rodent Population Surge
The breakdown across districts tells a grim story. Yau Tsim Mong registered 20,215 caught rodents last year, earning the top spot for infestations across the city. Other districts experienced alarming spikes in short order. Kowloon City saw catches shoot up by 83.5%. Sham Shui Po jumped 67.5%. Wong Tai Sin rose 26.4%.
So why are numbers soaring so fast?
Districts undergoing heavy urban renewal are bearing the brunt of the problem. In Kowloon City alone, more than 65 active construction and demolition sites are currently running. When heavy equipment breaks ground, it destroys subterranean nests and forces thousands of rats out of broken sewage lines straight onto residential streets.
Dense high-rises sitting on top of cramped restaurant alleys create perfect feeding grounds. Food stalls routinely leave unsealed food scraps in rear corridors overnight. Rats get free, easy access to high-calorie food water sources every single night, turning urban neighborhoods into ideal breeding environments.
Why Thermal AI Cameras Create a False Sense of Safety
To track infestations, officials rely heavily on thermal imaging cameras linked to artificial intelligence algorithms. These night-vision units scan targeted spots to calculate a metric called the Rodent Absence Rate. If a thermal lens captures snapshots with no moving heat signatures, that location earns a high "absence" score.
Government reports indicate that the citywide absence rate topped 90% across all 18 districts in late 2025. Outlying areas like Sai Kung boasted scores as high as 99.5%. Wan Chai and Kowloon City stood out as exceptions, with over ten specific spots dropping below an 80% absence rating.
Relying on camera scores as proof of victory misses how rodents actually live. Renowned international urban rodentologist Bobby Corrigan points out that thermal cameras offer only a single, narrow snapshot of activity. A camera can tell you if a rat walked directly through a specific light beam between midnight and 4:00 AM. It can't count burrows hidden inside public parks, track movement inside sewer mains, or estimate total colony size.
If rats shift their foraging path by ten feet to dodge a camera installation, the computer logs a 100% absence rate. The camera reports success while the street remains infested.
The Dangerous Health Risks Spreading in the Shadow
This isn't just about unpleasant smells or ruined trash cans. It's a genuine public health concern.
Hong Kong is an epicenter for rat hepatitis E, a virus transmitted when food or water gets contaminated by rodent waste. Dr. Siddharth Sridhar, a clinical associate professor of microbiology at the University of Hong Kong, notes that over 50 human cases have been identified worldwide, with local cases regularly raising red flags for medical authorities.
While some people suffer mild stomach issues or fever, severe cases trigger liver failure. Every time a humanContracts rat-borne hepatitis, it serves as a direct warning that urban pests are mixing far too closely with human supply chains.
Why Tokyo Succeeds Where Hong Kong Struggles
To fix a systemic pest crisis, authorities need to stop treating symptoms and start removing root causes. Public health experts frequently compare Hong Kong's struggle with Tokyo's rodent control practices.
Tokyo keeps street populations low through strict public compliance and waste separation. Food waste must be placed in reinforced containers or thick, sealed bags right before collection vans arrive, starving rats of evening meals.
Hong Kong's Food and Environmental Hygiene Department relies heavily on chronic anti-coagulant stomach poisons and traditional cage traps. Poison baits take four to five days to kill a rodent. That gives target animals plenty of time to crawl back into drainpipes or building cavities, while surviving rats learn to avoid the bait entirely.
Traps alone won't solve the crisis. Until illegal waste dumping behind restaurants is met with heavy fines and broken underground infrastructure is repaired, new rats will replace caught ones within weeks.
Practical Steps You Should Take Right Now
If you live or operate a business in an affected district, you can't wait for municipal teams to clean up your block. Take direct control of your immediate surroundings with these concrete actions:
Deny Food Access
Double-bag all food scraps and organic waste. Use heavy-duty plastic or metal trash bins equipped with tight-fitting lids. Never leave garbage bags sitting directly on alley pavement overnight.Seal Building Entry Points
Inspect your property's exterior walls and utility penetrations. Rats can squeeze through gaps as small as a quarter-inch (6mm). Pack open crevices with steel wool and cover them with quick-setting hydraulic cement or heavy steel mesh plates.Set Traps Correctly
Setting a single cage trap rarely works. Place at least six traps along wall bases where rats naturally run. Keep traps set for five consecutive days and check them twice daily. Use aromatic baits like fresh peanut butter, roasted pork, or fish scraps.📖 Related: the tree bar andHandle Trapped or Dead Pests Safely
Never handle rodents with bare hands. Put on plastic gloves and a face mask. Use tongs to place dead animals into a heavy plastic rubbish bag. Spray the carcass thoroughly with general household disinfectant or diluted bleach. Seal the bag tightly, drop it inside a second plastic bag, and call the government hotline at 1823 or your local hygiene office for collection.
Rats are ultimate opportunists. They flourish wherever humans get lazy with their waste. Catching 150,000 rodents a year sounds impressive in press releases, but fixing broken pipes, enforcing food waste disposal laws, and securing your own back door are what actually keep pests out of your home.
