High levels of bacteria have led to the suspension of daily water shows and the closure of a shallow play pool at the World Expo in Osaka, Japan, organisers announced on Thursday.
The decision was made after the complaints from visitors about swarms of tiny flying insects across the expansive waterfront site, where Expo 2025 will run until mid-October.
Since its opening in April, nearly six million people have visited exhibits representing more than 160 countries, regions, and organisations.
Although pre-opening surveys suggested public enthusiasm for the Expo was lukewarm, organisers say attendance has increased significantly in recent weeks.
Concerns have also been raised about environmental conditions at the reclaimed island site in Osaka Bay, which was formerly used as a landfill.
Organisers reported that high levels of legionella bacteria forced them to close a shallow water area where visitors, particularly children, would go to cool off.
This announcement followed a Wednesday statement in which organisers said that daily fountain shows featuring music and lights at an artificial pond had also been suspended due to the same health concerns.
The affected areas are currently being cleaned, and a decision on whether the shows will resume is expected by Friday.
Just days before the Expo’s opening, a potentially flammable level of methane gas was detected at the site.
More recently, insecticides have been sprayed to deter large swarms of non-biting midges that have been disturbing visitors.
Also known as the World’s Fair, the Expo tradition began in 1851 with London’s Crystal Palace exhibition and famously brought the Eiffel Tower to Paris.
Now held every five years in different global locations, the Expo serves as a showcase of culture, technology, and innovation.







