(Bloomberg) — New York City officials alarmed at a spike in coronavirus cases in Brooklyn and Queens neighborhoods with large Orthodox Jewish communities are bracing for the Yom Kippur holiday beginning Sunday evening. They fear hundreds crowding small, poorly ventilated synagogues will greatly increase the risk of transmission.

State regulations call for indoor religious services to limit gatherings to 33% capacity, with non-family related participants spaced 12 feet apart when singing or chanting. Many synagogues in the outbreak areas have relatively small prayer sanctuaries that would make it impossible to comply, said David Pollock, director of public policy for the Jewish Community Relations Council of New York.

Pollock’s organization has worked with hundreds of rabbis and community leaders to close streets for outdoor services, and to help plan for multiple services throughout the day Monday. The vast majority of synagogues have complied, with some offering only web-based services.

Throughout the Orthodox neighborhoods that are the focus of concern, though, hundreds of people likely won’t abide by social distancing or mask-wearing directives, he said. Many smaller houses of worship will be open and crowded, Pollock said.

“This is a frustrating situation, because, if you believe in science, we’ve done a lot to make safer alternatives available,” Pollock said. “If you’re sitting cheek by jowl with people chanting and singing indoors in poorly ventilated spaces, the risk is as high as it gets.”

Mayor Bill de Blasio said earlier this week that virus clusters in outer boroughs required “urgent action.” The rate of positive tests has hit 6% in the Brooklyn neighborhoods of Gravesend and Homecrest, 4.95% in Midwood, 3.53% in Borough Park and around 4% in the Queens areas of Edgemere Far Rockaway and Kew Gardens, according to Thursday’s advisory. Each neighborhood has large communities of Orthodox Jews. Mask-wearing compliance in these neighborhoods has been much lower than elsewhere in the city, officials said.

The New York area first experienced the Covid-19 pandemic in March when a cluster of more than 100 cases appeared in Westchester County’s community of New Rochelle, just north of the city. It forced hundreds within a mile of a synagogue to observe a quarantine. The outbreak occurred after a funeral and then a joint bar and bat mitzvah had attracted hundreds to the prayer center.

Health Inspectors

Yom Kippur, considered the Jewish religion’s most solemn holiday, begins at sundown and involves 24 hours of fasting and prayer. City officials have not said specifically what they intend to do about public-health violations during the holiday.

Inspectors were scheduled to be deployed Friday to private schools, including yeshivas, in outbreak areas. They will be checking for compliance with social distancing, mask wearing and hygiene, the mayor said. Four yeshivas have already been closed. The outbreaks run counter to the citywide test infection rate, which has hovered around 1% for more than a month.

Sound trucks will blare warnings in English and Yiddish, and ads have been posted in local weekly newspapers. But even that approach leaves challenges among Orthodox communities.

“Many of them prohibit the use of television all the time,” Pollock said. “Some are susceptible to the anti-mask mentality, and rumors of herd immunity even though the infection percentages don’t come close to achieving that. Leaders of the community are concerned, but they lack influence they once had.”

©2020 Bloomberg L.P.