Pittsburgh City Council on Tuesday approved letting developers build housing on smaller lots than they now can.

It may seem like an esoteric issue, but the move to shrink minimum lot size requirements is seen as an important step to unlock more land for residential development in the city and remove unnecessary obstacles for developers.

Depending on where in the city developers want to erect housing, the minimum lot size they can build on will shrink between 25% and 40% in most cases.

In some of the city’s densest areas, the requirements will be eliminated altogether once the bill — sponsored by Councilman Bobby Wilson, D-North Side — is signed by Mayor Ed Gainey.

While the vote was unanimous, some council members gave their support reluctantly, worried the measure would hinder efforts to pass broader zoning changes meant to aid low-income residents obtain affordable housing.

The minimum lot size legislation was pulled from a broader, controversial zoning package Gainey has pitched as a way to create more affordable housing.

That bigger proposal would expand inclusionary zoning — a mandate that all large housing developments earmark a portion of the units as affordable housing — citywide.

A competing bill introduced by Councilman Bob Charland, D-South Side, has further complicated zoning debates and sparked the ire of council members and housing advocates who support Gainey and his vision.

Charland’s bill would let neighborhoods choose for themselves whether to mandate affordable housing on new developments.

The battle over inclusionary zoning has become a political flashpoint ahead of the Democratic primary race.

Gainey’s backers on council worry that passing the minimum lot size proposal in isolation could kill the bigger bill, since there would be no more incentive for developers to accept citywide mandates to include affordable housing.

Councilwoman Barb Warwick, D-Greenfield, said her office helped draft the legislation initially included in Gainey’s bill. But she wasn’t happy to see it approved as a standalone measure.

“I wanted it with the inclusionary zoning, but aye,” she said as she voted in favor.

“This bill in isolation will not have the impact that it would’ve had as part of the larger package,” Councilwoman Deb Gross, D-Highland Park, said ahead of the vote.

“It’s no secret I am not for IZ citywide,” Coghill told TribLive after the meeting, adding he felt zoning changes like the minimum lot size bill would do more to attract developers and encourage affordable housing.