The mayor of Tokyo’s Shibuya district asked Halloween partygoers to avoid its streets this year, fearing the post-pandemic return of tourists may lead to chaotic mobs and crowd crushes like the fatal incident in Seoul last year.

“This year we are making it clear to the world that Shibuya is not a venue for Halloween,” Ken Hasebe said in a news conference on Thursday. People should avoid gathering in the area for festivities around Oct. 31, and drinking alcohol near the station will be banned for a few days around that time, he said. Stores in the area will also be asked to restrict liquor sales.

As Japan began embracing Halloween traditions over a decade ago, Shibuya’s streets, including its famous pedestrian crossing, became the unofficial party venue for young, costumed revelers. As the number of partygoers increased along with complaints about rowdy drinking and vandalism, authorities began ramping up security. Large gatherings were discouraged during the pandemic years, and crowds in recent Halloweens have been smaller and quieter than in 2019, when around 40,000 attended and some were arrested for overturning a vehicle.

Worries about crowd safety are running particularly high this year as this is the first Halloween since Japan fully lifted its Covid-related border restrictions. The return of foreign visitors has also prompted concerns over what some see as overtourism. Around 2.2 million people visited Japan in August, near pre-pandemic levels, according to Japan’s National Tourism Organization.

Hasebe said he feared there could be crowds of 50,0000 to 60,000 people or more if nothing were done.

“With no measures taken, the crowds will be incomparably larger versus last year. And we fear that this could possibly lead to a sharp increase in congestion-related accidents and incidents,” he said.

Japanese officials have also been on high alert after last year’s Halloween crowd crush in Seoul’s Itaewon district left over 150 dead. Aware that some tourists and young people will be undeterred by the request to stay away, the city will deploy 300 security guards, a 50% increase from last year. There will also be around 150 city officials warning people not to drink or smoke on the streets. However, Hasebe said ultimately people cannot be arrested for drinking or smoking on the streets by law, but they could be arrested for engaging in misconduct like starting a fight.

Kerona Slater, a 34-year-old school teacher who moved to Japan from Jamaica in 2015, plans to go with friends in her Little Red Riding Hood costume.

“I think a lot of us will be a bit more cautious, but I do think a lot of people will still be going,” she said. “Especially the younger crowds, they’ll be going. And foreigners, we tend to not be as passive or submissive as the Japanese, so I think a lot of foreigners are going to be going as well.”

Hasebe acknowledged that there is just a “50-50” chance of the measures working, but said he hopes that by getting the message out early he can persuade foreigners to avoid coming to Shibuya for Halloween.

“We hope that this goes well, but we don’t know yet, and that’s why I am anxious,” he said.