San Francisco lived up to its reputation as the nation's NIMBY capital this week by voting to reject a proposed apartment project over concerns that the new building would cast too much shadow on a nearby park.

On Tuesday, the city's Board of Supervisors unanimously voted to delay the approval of a 63-unit apartment building slated to be built on Folsom and Russ Street in the city's SoMa neighborhood. The project is being sponsored by developer Golden Properties LLC, and has been working its way through the approval process since August 2017.

Despite the fact that Golden Properties' development would add new units of housing to a city in desperate need of it, supervisors thought the building's costs would outweigh any benefits.

"We absolutely need more housing and affordable housing," said Supervisor Matt Haney to the San Francisco Chronicle, but "this isn't a meaningless shadow on someone's backyard. This is a shadow that falls on the only multi-use public park in SoMa."

Indeed, the proposed six-story building would, on the longest day of the year, cover an additional 18 percent of nearby Victoria Manalo Draves Park—which boasts a community garden, basketball court, and softball field—in shade, according to a study performed by the city's Planning Department.

That might not sound like much, but it has been a sticking point for the South of Market Community Action Network (SOMCAN), a neighborhood group that has fiercely opposed the project and the additional shadow it would cast. Thanks to the byzantine nature of San Francisco's development regulations, the group has had ample opportunity to delay the Folsom project.

San Francisco's planning code prohibits new buildings from casting shadows on public parks managed by the city's Parks Department if those shadows are found to have an "adverse impact." However, what exactly counts as an "adverse impact" is ultimately left up to the city's Planning Commission to decide. In a heated commission hearing on the project in December 2018, community activists spoke about the perceived damage the project would do to the neighborhood.

"The scale and size of the project seems to be monstrous," said one member of SOMCAN, who also stressed the severe impact of the building's shade, saying "any wet surfaces in the park that are shaded will continue to be wet, damp, and cold for a longer period after the shadow passes."

Other neighborhood opponents expressed concern about the displacement of existing commercial tenants at the lots that were to be redeveloped into housing, or otherwise bemoaned the impacts on precious open space in an area of the city sorely lacking in it.

These arguments proved persuasive for some commissioners, with one saying that she'd "never supported any shadow on any park unless a project was 100 percent affordable or served a community purpose larger than private development."

Nevertheless, commission voted to approve the project in a tight 4-3 decision.

That did not end the controversy, however. SOMCAN then appealed to the San Francisco Board of Supervisors, arguing that there had been insufficient study of the shadow question.

This time, the group was luckier, convincing a unanimous board to send the project back to the Planning Commission for further review. Given how fast costs for materials and labor are rising in the Bay Area, a delay of even a few months can cost developers hundreds of thousands of dollars.

This gives SMCAN incredible leverage to get more concessions from Golden Properties; possibly getting the developer to agree to a reduction in the size of their Folsom project, or an increase in the number of below-market-rate units it will include.

This series of events is hardly unique to the Folsom project. Indeed, it bears a striking similarity to another proposed San Francisco apartment project profiled by Reason.

In that case, property owner Robert Tillman has struggled for years to get permission to redevelop a laundromat he owns into 75-unit apartment building in the neighboring Mission District over the objections of community activists who've argued that his laundromat is a historic resource, and that the shadow it would cast on a nearby school park would be detrimental to the health and safety of neighborhood children.

A big difference between the two cases is that the Board of Supervisors' decision to delay the Folsom project has earned it some sharp criticism from San Francisco Mayor London Breed.

"You cannot claim to be pro-housing and then reject projects like this one," tweeted Breed, a self-identified YIMBY (Yes in my Back Yard) who won election in June 2018 on a pro-housing platform. "Low- and middle-income folks continue to be pushed out of our city. Average rent for a one-bedroom apartment is ~$3,600. We. Need. More. Housing."

The irony is that Breed, in one of her last acts in her previous job as city supervisor, bowed to the demands of neighborhood activists, and voted to delay Tillman's project for lacking sufficient shadow study.