Given that suspected transmissions were identified in some restaurants at the beginning of the fifth wave of the epidemic, the EMSD assisted relevant departments in conducting epidemiological investigations by inspecting the operation of the ventilation systems and measuring the airflow on site. To minimise the risk of transmission of COVID-19 in food premises, we also carried out site inspection at about 50 restaurants to check whether the rate of air change met the relevant ventilation requirements. Moreover, the EMSD immediately conducted deep cleaning and disinfection of the ventilation systems and installed ultraviolet-C sterilisers at the escalator handrails in public markets and cooked food centres of the Food and Environmental Hygiene Department, and installed air purifiers in the offices of public markets, refuse collection points and public toilets in various districts to reduce and prevent virus infection and protect the health of tenants, staff and members of the public.