Osaka –

With just six months to go before the 2025 World Exposition in the city of Osaka, there are still a host of challenges for organizers such as the slow sale of advance tickets.

The Osaka Expo is scheduled to take place on Yumeshima, an artificial island, from April 13 through Oct. 13 next year.

A ring-shaped roof with a circumference of around 2 kilometers — one of the world's largest wooden structures, now regarded as a symbol of the expo — has been completed, while the construction of foreign pavilions, which had been slow, has entered its final stages.

As of Wednesday, about 7.14 million advance tickets had been sold since they went on sale at the end of November last year — only 51% of the organizers' target of 14 million.

"We're a little concerned about whether the target will be achieved," a business leader in the Osaka area said.

Organizers have pinned high hopes on the display of a rock from Mars to increase momentum for the expo. The rock is one of the world's biggest samples of a meteorite from Mars collected by a Japanese Antarctic research expedition.

Music events are also scheduled to take place, including an opening performance by popular Japanese singer Ado.

"We want young people to be interested" in the expo, said an official at the Japan Association for the 2025 World Exposition, which organizes the Osaka event.

To enhance people's interest in the expo outside of the Osaka area, the association opened an information center in Tokyo on Sept. 25 to promote the event and sell souvenirs.

The Japanese government plans to give lectures on the expo at schools across the country and promote exchanges between people from foreign countries participating in the event and local residents.

The challenges include transportation bottlenecks. Osaka Metro's Chuo subway line is the sole railway route for access to Yumeshima, a situation expected to leave trains crowded.

Some local companies have allowed employees to work remotely or commute during off-peak hours on a trial basis at the requests of the Osaka city and prefectural governments.

To ensure the safety of visitors, the association is considering cooperating with neighboring local governments in case the expo venue is isolated following a disaster.