A Manhattan community group has filed a lawsuit seeking to overturn the city’s landmark rezoning of Midtown South, alleging the outgoing Adams administration and city planning officials violated state environmental law and New Yorkers’ constitutional right to a healthy environment.

The Midtown South Mixed-Use (MSMX) plan permits residential development in 42 blocks spanning between West 23rd and 40th Streets and Fifth and Eighth Avenues. Over 2,800 of the planned 9,500 residences would be rent-regulated affordable units.

The petition, filed in New York State Supreme Court last week on behalf of the Midtown South Community Council, argues the MSMX, one of the city’s largest neighborhood rezonings in decades, was approved without legally required mitigation for significant environmental impacts disclosed in the city’s own environmental review.

The lawsuit claims that the city violated the State Environmental Quality Review Act (SEQRA), the City Environmental Quality Review (CEQR) process, and the state’s Green Amendment, which guarantees residents the right to clean air and a healthy environment. The petition asserts the city failed to address air-quality hazards, displacement risks, loss of open space, threats to historic resources, and traffic congestion expected to result from rezoning the 42-block district for new residential development.

The group is asking the court to annul the rezoning and compel the city to prepare a supplemental environmental impact statement.

A spokesperson for the city’s Law Department said the administration is reviewing the lawsuit but defended the rezoning process.

“We will review the lawsuit. We are confident in the rigor of the environmental review conducted as a part of this plan, which is a win-win-win for Midtown South, bringing more homes, more jobs, and more investments to this transit-rich, central community,” the spokesperson said.

The City Council approved the Midtown South plan in August, allowing for more than 9,500 homes, including several thousand affordable units, in an area long dominated by office and manufacturing uses, where new housing was previously largely prohibited.

The lawsuit disputes those projections, arguing the rezoning includes no enforceable guarantees on affordability and could result in the loss of existing rent-regulated housing.

City officials have characterized the plan as a major step toward addressing the housing shortage and revitalizing a centrally located commercial district. The final plan also included approval for a car-free busway on 34th Street, a proposal that had recently stalled, as well as a $122 million fund to support Garment District businesses.

The rezoning plan marked the first time the city utilized the Adams administration’s  “City of Yes” land-use initiative, which the City Council approved last December to permit high-density districts with larger residential buildings in response to the city’s housing crisis. 

However, the lawsuit argues that the city’s own Final Environmental Impact Statement identified unmitigated risks, including elevated cancer-related air quality concerns near certain development sites, and that the city unlawfully proceeded without addressing them.

It further claims the city failed to consider reasonable alternatives or provide a legally required “reasoned elaboration” for rejecting mitigation measures, as required under SEQRA.

The lawsuit notes that Manhattan Community Board 4, which oversees the area, voted 36–4 against the rezoning during the public review process, citing concerns over air quality, open space and displacement.