It's On in Harlem! Again.

More than four years after the concept was first presented, and four months into the city’s public approval process, the

More than four years after the concept was first presented, and four months into the city’s public approval process, the Bloomberg administration’s plan to rezone 125th Street appears to be facing mounting opposition.

Numerous advocacy groups plan to critique the proposal at a City Planning Commission hearing scheduled for Jan. 30, and Manhattan’s Community Board 10 has been holding workshops that prepare residents to deliver testimony in preparation for the meeting. Such actions come as Borough President Scott Stringer last month gave a formal disapproval of the plan; a new advocacy group called VOTE People has formed to oppose the plan outright; Community Board 10 has issued a resolution with a long list of critiques after two packed hearings on the subject; and even the store-owner-and-landlord-backed 125th Street Business Improvement District is upset about a large component of the initiative.

Why all the fuss?

The rezoning seeks to transform the already-lively street into a bustling hub of business, arts, culture and shopping through larger and taller new construction along the thoroughfare. While community leaders say they welcome the concept of injecting a new vitality into 125th Street, worries of gentrification, housing affordability and displacement have fueled criticisms of numerous aspects of the city’s plan.

The proposed zoning change is hardly the largest or the most radical of the Bloomberg administration. In 2005, the city allowed for a transformation of Manhattan’s West Side, and it also opened the gates for thousands of new apartments in the Greenpoint/Williamsburg rezoning. But the 125th Street action is significant in both its scope and detail.

But the 125th Street plan is certain to be regarded as one of the most significant. The rezoning lies in the heart of one of the densest residential neighborhoods in the city, on what is perhaps the city’s most historic African-American thoroughfare, at a time when gentrification and displacement are major concerns throughout the city.

The plan is centered around the desire to establish 125th Street as a regional hub, a vision that planners seek to realize by allowing for developers to create buildings with substantially more density than is currently allowed, especially on the north end of the street in the center of the district.

In all, the plan would allow for approximately 2,300 new apartments and more than 600,000 square feet of new office and retail space—development that would presumably fill in the vacant lots and replace the one-story retail shops that line 125th.

In what is likely a nod to the street’s history and cultural significance, the plan seems to be one of the more meticulously crafted initiatives to come out of the Department of City Planning under Amanda Burden, the notoriously detail-focused chairwoman of the agency. Banks are forbidden from having large lobbies on the ground level so as to keep the street life vibrant; shop owners are prohibited from coating their storefronts with solid roll-down metal grates after they close; and theaters are permitted to build new marquee signs, an action not generally permitted citywide.

And while community groups have applauded certain aspects of the plan, such as an “arts bonus” that allows developers to build to the maximum density only if they include an artistic component, the city is seeing widespread criticism about other aspects.

Most controversial is Ms. Burden’s insistence on allowing for new residential development. While builders would likely take a development bonus and set 20 percent of the units aside as affordable, the prospect of up to 1,800 market-rate condos being built in the heart of Harlem (a number the environmental impact statement lists), a neighborhood with a median household income of less than $22,000 in 1999, is unsettling.

“We are against luxury residential developments,” said Franc Perry, the chairman of Community Board 10. Already, he added, “the concern is that people are being displaced and there’s no place for them to go.”

It's On in Harlem! Again.