In response to the prolonged rain on recent days, the Food and Environmental Hygiene Department (FEHD) will continue to collaborate with relevant departments and stakeholders to strengthen mosquito control and elimination efforts. These include removing stagnant water at construction sites and locations with higher mosquito infestation risks, and eliminating adult mosquitoes. The FEHD also urges members of the public and stakeholders, including property management companies and construction sites, to step up inspections and remove stagnant water in their areas to prevent and control mosquito infestation.

     ​A spokesman for the FEHD said today (August 6) that, repeated heavy rain may wash away pesticides previously applied in the environment and lead to increased water accumulation. Sites where stagnant water and mosquito breeding were once detected may now have shifted. The FEHD is therefore continuing to work with relevant departments and stakeholders to intensify inspections of high-risk locations prone to water accumulation after heavy rains, including construction sites, works sites and spots that have previously recorded high gravidtrap indices. If stagnant water is found to be a potential mosquito breeding ground, it will be removed immediately. Larvicides such as temephos sand granules will be applied to stagnant water that cannot be cleared, and ultra-low volume fogging operations will be carried out in adult mosquito habitats such as densely wooded areas, dark and secluded places, and abandoned structures to eliminate adult mosquitoes.
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     ​The FEHD has also collaborated with District Councils, District Offices, and relevant stakeholders to strengthen publicity and education efforts, and to conduct joint clean-up operations targeting mosquito breeding blackspots (such as public areas in "three-nil" buildings) in the districts to further curb mosquito breeding.

     August is Hong Kong's rainy season, and hot, rainy weather fosters rapid mosquito breeding. The FEHD reminds members of the public and stakeholders to continue mosquito prevention efforts and remove stagnant water to reduce mosquito breeding opportunities. Effective mosquito control requires the collaborative efforts of the public and all sectors.

     Members of the public should remain vigilant and promptly take special mosquito prevention and control measures at home and in other environments during heavy rain. These measures include:
 

• Check home environment (outdoor and open areas in particular) for stagnant water, which can easily lead to mosquito problems;
• Check household items (those placed in outdoor and open areas in particular), such as refuse containers, vases, air conditioner drip trays, and laundry racks, to prevent stagnant water;
• ​Cover water containers such as buckets and basins; and
• Check and clean areas prone to stagnant water at least weekly to prevent mosquito breeding.

 
     ​Person-in-charge of property management companies and schools should take the following measures to prevent mosquito breeding caused by rain:
 

• Inspect common areas of the property/school for large areas of stagnant water, and arrange for the removal of stagnant water and filling of sunken areas;
• Check drain gates and outlets for blockage by dead leaves or rubbish, and keep drains clear;
• Check umbrella stands, umbrella tubes, and air-conditioner drip trays to prevent stagnant water;
• ​Properly dispose of water containers and place rubbish in covered bins;
• ​After heavy rain, manhole keyhole fillers, adhesive tape, or plastic keyhole covers may be washed away by rainwater. These should be refilled with sand or covered with plastic keyhole covers or adhesive tape; and
• Inspect green areas including flower pots, flower beds or gardening areas, and remove stagnant water to prevent mosquito breeding.

 
     ​Construction site managers should also conduct early assessments and implement effective measures to prevent mosquito infestations. These measures include:
 

• Inspect the construction site during and after heavy rain to ensure there is no stagnant water that could breed mosquitoes. If large areas of stagnant water are present, they should be emptied as soon as possible using tools like a pump;
• ​Check water barriers or other items (such as canvas for covering) for stagnant water. Bamboo scaffolding should have its end caps sealed with fine sand or drilled through to prevent water accumulation; and
• If stagnant water is difficult to remove, apply larvicides such as temephos sand granules as appropriate.

 
     ​Members of the public may refer to the FEHD's webpage on mosquito prevention and control (www.fehd.gov.hk/english/pestcontrol/risk-pest-mosquito.html), and should constantly pay attention to the information regarding chikungunya fever released by the Centre for Health Protection of the Department of Health. The public should call 1823 in case of mosquito problems.

Ends/Wednesday, August 6, 2025
Issued at HKT 21:16

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