After a Taylor Swift fan died Friday during a sweltering Rio de Janeiro stop in her Eras Tour, the singer took to Instagram to express her grief. But Rio's mayor is demanding more than platitudes, and is seeking changes to how concerts are run in the Brazilian city.

The concert was the first of three Swift shows planned for Estádio Olímpico Nilton Santos, a 16-year-old, 70,000-seat venue in Rio. The region is experiencing a record-breaking heat wave, according to the Weather Channel, with a daily high of around 103 degrees Fahrenheit, but with a heat index that makes it feel like 125. As Estádio Nilton Santos is an open-air stadium, that means fans are unprotected from the evening heat, which typically drops from daytime by only 15 degrees.

Those are the circumstances faced by 23-year-old Ana Clara Benevides Machado, a Swift fan who collapsed at Friday's show, event organizers Time for Fun announced via an Instagram post written in Portuguese.?

“Last night, Ana Clara felt unwell and was promptly attended to by the team of firefighters and paramedics, being taken to the medical center at the Nilton Santos Stadium for first aid protocol,” the post reads.?

"Given the situation, the medical team chose to transfer her to Salgado Filho Hospital, where, after almost an hour of emergency care, she unfortunately died. To the family and friends of Ana Clara Benevides Machado, our sincere condolences."

Even before Machado's name was known, Swift had announced her passing, in an Instagram story set to expire on Saturday evening. “I can’t believe I’m writing these words, but it is with a shattered heart that I say we lost a fan earlier tonight before my show," Swift wrote.

“I can’t even tell you how devastated I am by this. There’s very little information I have other than the fact that she was so incredibly beautiful and far too young." (Vanity Fair contacted a Swift representative for comment, but has not received a response as of publication time.)

Brazil's mayor, Eduardo Paes, called Machado's death “unacceptable” in a statement posted to X (formerly Twitter). Writing in Portuguese, he said that he has “ordered the municipality's Executive Chief of Operations to demand action with the production of the show,” including plans to keep early-arriving fans out of the sun's glare, water distribution points throughout the stadium, and additional ambulances at the stadium.?

Flávio Dino, Brazil’s justice minister, announced emergency rules for tonight's show on X that also include increased access to water for fans. In addition, his “team is heading to the location of today's event" to monitor safety and conditions, a spokesperson said via statement.

Time for Fun says that they're hustling to comply with the new rules, announcing through Instagram that free water will be available at all stadium access points, and that rules against outside food and water will be lifted given the heat wave. (Those items must be sealed; metal, aluminum, and Thermos bottles are prohibited.)?

One thing concert attendees won't see is an acknowledgment by Swift of Machado's death. “I’m not going to be able to speak about this from the stage because I feel overwhelmed by grief when I even try to talk about it,” Swift said via Instagram.

"I want to say now I feel this loss deeply, and my broken heart goes out to her family and friends. This is the last thing I ever thought would happen when we decided to bring this tour to Brazil.”

Swift's last Rio show is on Sunday, Nov. 19. She returns to the Brazilian stage on Friday, Nov. 24, for a three-day stint at Allianz Parque in S?o Paulo, where the weather is currently expected to be stormy with a high of 75.