The controversial proposal to charge drivers in the busiest parts of Manhattan took a major step forward on Monday, with Mayor Michael R. Bloomberg and Speaker Christine C. Quinn wrenching approval from the City Council by an unusually slim margin.

Under intense pressure from the mayor, Ms. Quinn and their allies that continued almost until the voting began, council members approved the plan to charge most drivers $8 to enter a zone below 60th Street by a vote of 30 to 20, with no abstentions and one absence.

At a news conference after the vote, where Mr. Bloomberg made a rare appearance on the speaker’s side of City Hall, officials sought to play down the narrowness of their hard-won victory, among the closest of this administration in a body that typically votes in near unanimity.

Approving the proposal, Ms. Quinn said, would send a message to the Legislature that the “people who were elected to represent the New Yorkers who live in our five boroughs are sick and tired of our streets being clogged with traffic, we’re sick and tired of the children who live in our city literally having to fight to be able to breathe, and that we see congestion pricing as a solution to this problem.”