The Cambridge City Council postponed a vote on a proposal to make Harvard Square a historic district Monday, saying that the proposal did not have enough support for approval.

A committee will now look into the idea of making the Square a conservation district instead, which would not give the same level of protection to historic buildings that an historic district would.

"Historic district are established under general laws which are very strict about what things have to be reviewed," said Charles M. Sullivan, executive director of the Cambridge Historical Commission.

Creating an historic district would give the a commission "binding review over demolition, new construction, and publicly visible exterior alterations to existing buildings."

According to Sullivan, conservation districts can be "tailored to the particular needs of a neighborhood," and do not establish the same binding review procedures as an historic district.

Another major distinction between historic districts and conservation districts involves the rights of non-profit organizations.

Under historic districts, non-profits groups--such as the Harvard Square Defense Fund--have legal standing to appeal decisions made about the historic district.

"There is concern in Harvard Square because there has been so much litigation in the last 25 years," Sullivan said.