People entering a wide variety of businesses in the city of Los Angeles began having to show proof of COVID-19 vaccination on Monday as one of the country’s strictest measures intended to slow spread of the coronavirus took effect.

The new rule covers businesses ranging from restaurants to shopping malls and theaters to nail and hair salons, however the city said it won’t start enforcing the law until Nov. 29.

The new requirements, however, do not apply to Long Beach or parts of Los Angeles County outside of LA. Long Beach aligned with the county in requiring vaccination proof only for bars and other drinking establishments that do not serve food.

While not required, Long Beach officials “strongly recommends” restaurant owners require vaccine verification for indoor dining.

Business trade groups say the new LA mandate will sow confusion because Los Angeles County’s own vaccine rules — which apply to dozens of surrounding communities — are less sweeping. Cities are allowed to pass rules more stringent than the county’s.

“There’s a tremendous lack of clarity,” said Sarah Wiltfong, senior policy manager at the Los Angeles County Business Federation. For example, most retail shops are exempt. “But shopping malls and shopping centers are included, which of course includes retail shops,” she said.

Harassment of workers who are tasked with verifying vaccination is the top concern of the business federation’s members, Wiltfong said.

“This puts employees in a potential position of conflict, when they’re not necessarily trained to handle situations like that,” she said.

Los Angeles is among a growing number of cities across the U.S., including San Francisco and New York City, requiring people show proof of vaccination to enter various types of businesses and venues. But rules in the nation’s second-most-populous city, called SafePassLA, apply to more types of businesses and other indoor locations including museums and convention centers.

They are being implemented as new cases have started inching up following a sharp decline from an August peak driven by the delta variant.

This was the time of year in 2020 when the worst spike of the pandemic was just beginning in California, which by January saw an average of 500 people die every day. Los Angeles became the state’s epicenter and its hospitals were so overloaded with patients that ambulances idled outside with people struggling to breathe, waiting for beds to open.

So many people died that morgues reached capacity and refrigerated trucks were brought in to handle the overflow. That stark scene played out as coronavirus vaccines arrived and California and Los Angeles moved aggressively to inoculate people.

Among LA county’s roughly 10 million people, 80% of eligible residents now have received at least one COVID-19 vaccine dose and 71% of those eligible are fully vaccinated, according to public health officials.