Housing advocates had much to celebrate Thursday.

The City Council approved a sweeping measure requiring developers seeking city subsidies for large residential projects to set aside 15 percent of units for the homeless.

It's a small victory for New Yorkers like Nathylin Flowers Adesegun, a housing advocate who for years has joined other activists calling on the administration to build more units, so that people currently living in shelter, like her, can move into permanent housing.

Paulette Soltani, Political Director at VOCAL-NY, a group which has been pushing for the changes, said the changes will help thousands of people get into permanent housing.

"The principle of this says that when the city has resources to use, it has to use them on human need, so when the human need is so great, we should be using our city dollars to house the people who need it most," Soltani said.

The measure was sponsored by Bronx Democrat Rafael Salamanca, who has been critical of the mayor's affordable housing plan, saying it does little to create permanent housing for those in shelter while also pushing out neighborhood residents through rezonings that lead to displacement.

Mayor Bill de Blasio initially opposed the bill, but a spokesperson said he now supports it.

Salamanca credited Council Speaker Corey Johnson with getting the bill over the finish line.

Johnson said the change is likely to create other policies that might lead to a more permanent fix to the city's ongoing homelessness crisis.

"This is a revolutionary change in policy that is both necessary, right and urgent. Close to 80,000 people are experiencing homelessness right now in New York City," he said.

The bill is expected to create 1,000 units of housing starting in July of 2020.

The bill will now be sent to the mayor's desk for his signature.