Organizers of Bat Fest, scheduled for Aug. 28, said they feel the city has forced them to cancel.

In an Aug. 26 post, organizers said they received an email just before 5 p.m. Aug. 25 informing them that the city denied the music festival's special event permit.

"Therefore, we have been strong-armed into cancelling our event," the post said. "We are shocked and devastated as this is a huge financial blow and harmful to our reputation as event producers. We know it’s also hard on our ticket holders, our vendors, our bands, [et cetera]."

With emergency rooms full and Austin Emergency Medical Services strained, Mayor Steve Adler said the Austin Public Health Authority nixed the large event.

Event organizers said their COVID-19 Safety Plan had been approved by the city, the Austin Police Department and the Austin Fire Department, while Austin Emergency Medical Services medics were scheduled for the event. They also felt "singled out arbitrarily and discriminated against," the post said.

Mayor Steve Adler said he is "heartbroken" over the postponement.

"In this city, it’s going to be really hard for us to have big events," Adler said. "Because when you have big events, it increases the number of people who get in accidents, who get heat issues and EMS is called. There’s just more people. And that’s important to note because the choice not to get vaccinated, which is leading to the number of people in our emergency rooms—in our ICUs—is now having an impact on the events that we can have and not have in this community."

On Aug. 24, Austin Public Health expressed concern that large events could strain the city's already maxed-out health care system, raising questions about the likelihood of many fall events happening.

The festival will offer full refunds or the option to transfer this year's tickets to the 2022 festival.

Ben Thompson contributed to this report.