SAN FRANCISCO—On Wednesday, March 15, the home sharing startup Airbnb announced it has taken down 923 home listings in San Francisco.

In a story reported by CNET, the listings apparently violated Airbnb’s “One Host, One Home” policy, which aims to limit the number of listings a homeowner can post on the Airbnb platform, with a few exceptions. The policy forms part of Airbnb’s attempt to address criticism that it is distorting the value of properties in cities around the world.

In July 2016, California senator Diane Feinstein joined senators Elizabeth Warren and Brian Schatz in calling for a regulatory probe of short-term rental websites, writing in a letter to the U.S. Federal Trade Commission, “We are concerned that short-term rentals may be exacerbating housing shortages and driving up the cost of housing in our communities.” There is a widespread concern that services such as Airbnb make visiting cities cheaper, but living their full-time more expensive, because landlords can increase short-term profits by renting out to tourists.

Airbnb released a report on its site in February that addressed such concerns. While the company has worked with regulators to address some of the issues around rent control, they argued that their service helps urban residents survive in areas that are increasingly expensive, helping provide financial security amidst widespread gentrification. The report writes, “the median annual earnings citywide is $10,900, an economic life preserver for many hosts who are struggling to live in an increasingly expensive city.”

The exemptions to the “One Host, One Home” policy include: co-hosting, when a host temporarily manages someone else’s listing; licensed hotels and Bed and Breakfasts; units with at least a 30-night minimum requirement; accessory dwelling units (ADUs), in-law units and basement units that are part of someone’s home, but are listed separately.

Airbnb was founded in San Francisco in 2008 by Brian Chesky, Joe Gebbia and Nathan Blecharczyk. The service boasts over 100 million users and a valuation estimated at $30 billion.