Hong Kong’s homeless population faces escalating health risks as rising temperatures lead to worsening pest infestations and leave individuals on the street more vulnerable to heatstroke, a local NGO has said.

Homeless people in Sham Shui Po, on February 4, 2025. File photo: Kyle Lam/HKFP.

ImpactHK said on Sunday that extreme weather alternating between record-breaking heat and heavy downpours has created the ideal breeding conditions for pests, such as mosquitoes and midges, at locations where the city’s unhoused congregate.

The NGO conducted environment monitoring and pest sampling over 15 days between July and August to identify pest risk at four sites. Over 60 questionnaires were also collected from the sites’ occupants.

Across the four locations surveyed, Cherry Street Pedestrian Subway in Tai Kok Tsui recorded the highest pest density – a total of 348 insects were collected over the sampling period, averaging 23.2 per day, according to the NGO. The semi-enclosed tunnel also had an average relative humidity of 87.9 per cent.

Tung Chau Street Park in Sham Shui Po saw 135 pests captured over nine monitoring days, averaging 15 per day, the NGO said.

Heatstroke risk

Meanwhile, survey respondents reported experiencing more severe pest problems on the street compared with staying in hostels. Cockroaches, rats, midges and fleas were identified as common problems.

“Infestation rates of cockroaches and rats reached 79 [to] 83 per cent at parks, tunnels and footbridges, while 100% of respondents at the [Tsim Sha Tsui] Cultural Centre reported midge problems,” ImpactHK said in a statement.

ImpactHK holds a press conference on September 6, 2026, on the health risks posed by pest infestation and extreme heat to the city’s homeless population. Photo: ImpactHK.

Three-quarters of respondents reported severely disrupted sleep due to pests and bites that led to skin inflammation or secondary infection, the NGO said, adding that 18 per cent found their financial troubles exacerbated by having to buy mosquito repellent.

Extreme heat also poses severe health risks to homeless people, the survey found, with 62 per cent of respondents reporting severe sleep disruption during heat warnings. Over 37 per cent experienced heatstroke symptoms such as dizziness, headaches, and nausea.

A man surnamed Chow, who had lived on the street in Causeway Bay for more than five years, said pests made sleep “impossible” and urged the government to open air-conditioned heat shelters daily throughout the summer.

Homeless people in Mong Kok, on February 4, 2025. Photo: Kyle Lam/HKFP.

“Our hands and feet are covered in bites. I hope the temporary heat shelters can be opened daily and for longer hours throughout July and August, instead of waiting until the Very [Hot] Weather Warning above 33°C is issued before allowing the public to use them,” Chow was quoted as saying in ImpactHK’s statement.

‘Keep shelters open’

The NGO urged authorities to keep shelters open throughout the summer to address the impact of rising temperatures on homeless people, and to ensure that shelters are located within a 15-minute walk from residents.

It also recommended extending the opening hours of public bathhouses, noting that nearly half of its surveyed respondents struggled to find a place to bathe.

Medical outreach teams with pest prevention supplies should be deployed more frequently, the NGO added, and homeless people should be designated a priority group at the city’s District Health Centres.

The Intergovernmental Panel on Climate Change has warned that the intensity and frequency of heatwaves have continued to increase since the 1950s due to human-caused climate change. The prevalence of greenhouse gases like carbon dioxide – which trap heat in the atmosphere – raises the planet’s surface temperature, with hotter, longer heatwaves putting lives at risk.

See also: How extreme heat became the deadliest silent killer among world weather disasters

Hong Kong has already warmed by 1.7 degrees Celsius since the Industrial Revolution, research NGO Berkeley Earth says. Heat and humidity may reach lethal levels for protracted periods by the end of the century, according to a 2023 study, making it impossible to stay outdoors in some parts of the world.