On the surface, this summer's decline in the number of people living in the subway system is a positive sign, but the decrease barely makes a dent in the homeless problem that plagues the city. Far more must be done.

In the first year of an effort by the city's Department of Homeless Services to partner with the MTA on outreach underground, 450 people were moved from the transit system to some type of housing, city officials said. Of those tracked by the city, 158 remain in the subways.

Citywide, about 56,000 people were living in shelters as of June, according to the Department of Homeless Services. Thousands more live on the streets.

That's unacceptable. NYC must find ways to care for its neediest. It's a complicated issue with no easy fix. People cannot be forced off the street, and many have other difficulties, such as mental illness, that must also be addressed.

We shouldn't draw any hard conclusions from data on homeless people underground, especially because, advocates said, those individuals are often transient, moving between the streets and subways. It's also impossible to know to what extent warm weather, stifling subway platforms or other factors lead some to leave the transit system.

But the city's new outreach effort helped. Officials pointed to the NYPD's involvement, which paired officers with counselors and psychiatrists to reach homeless people underground. NYPD statistics show a decline in arrests for crimes like panhandling in the subways, which may mean the outreach teams are providing help without charging people with crimes.

The city should broaden similar outreach on the streets and fold in specific programs like Mayor Bill de Blasio's NYC Safe for those who are homeless, mentally ill and violent. But that's not enough. The city needs a more comprehensive solution primarily focused on developing more units of affordable, supportive and transitional housing. Getting more of the city's homeless people the help they need and places to go won't solve the whole problem, but they are critical steps to care for those who need it most.