Last year, Cambridge, Mass., passed one of the most ambitious housing reforms in the U.S., which has unleashed a flurry of new development.

The city of 120,000 had seen new housing projects dry up largely due to restrictive zoning and a lack of buildable lots. The new zoning rules allow four-to-six-story residential buildings to be built on nearly any residential lot with minimal input from neighbors or city boards.

This year, Cambridge has permitted about 400 new homes, including many small and midsized multifamilies that were not previously allowed, with many more expected to come, according to a Boston Globe report. There has been a notable increase in four-story projects of three to nine units, a size that avoids an affordable housing requirement

The reforms have provoked backlash, with the report citing one project that consists of a teardown of a single-family house on a tree-lined cul-de-sac to be replaced with a 56-unit, six-story apartment building that will closely abut neighbors. Neighbors say they are considering litigation to stop this project. It appears to be an outlier in size and scope, though.

Another complaint is that some projects are replacing fairly affordable old homes with more expensive ones. The City Council continues to support the zoning reform but is reportedly considering revisions to the rules that could limit allowable square footage of new units.