Many of us were haunted last fall by the story of Dasani — one of the 22,000 children living in homeless shelters in New York City, and a student at the McKinney Secondary School of the Arts in Brooklyn. The New York Times followed her and her family through bureaucratic indignities, the insecurity of shelters and temporary apartments, and other false starts. Her school was her anchor.

It is with Dasani in mind that we welcome the news of Mayor Bill de Blasio’s ambitious plan to build or preserve 200,000 units of affordable housing, costing $8.2 billion over 10 years. It is an important step toward helping families like Dasani’s who have been pushed to the margins of the city by rising rents. The plan addresses the needs of both New York City’s lowest-income residents and middle-income workers, including the UFT’s own members, who increasingly find themselves priced out of the city.

Under the mayor’s plan, developers will for the first time be required to include affordable units in any residential construction. And the city has vowed to more aggressively protect tenants in rent-regulated units.

Landlords that have been ruthless in hounding out tenants — especially by withholding repairs and services — should feel the full weight of the law. Both federal and state assistance will be needed to help families on the lowest economic rung make the transition from shelters to stable housing.

The plan is a long overdue response to the growing housing costs that have priced out many families. Change cannot come soon enough for our students and families.

The New York State Technical and Educational Assistance Center for Homeless Students reports that 80,574 city public school students were identified as homeless in the 2012–13 school year — living in shelters or motels, or doubled up with their families in inadequate housing.

As any teacher can tell you, the lack of stable and secure housing reverberates in the classroom. The state assistance center has the sad tally: More than 75 percent of homeless children read below grade level, and 36 percent of homeless children repeated a grade, twice the rate of other children. Students with two or more school changes are half as likely to be proficient in reading as their peers.

For the youngest students, the impact is especially profound. The Institute for Children, Poverty and Homelessness found that children experiencing homelessness or high mobility begin Head Start at age 3 “with poorer socio-emotional, cognitive, and health-related outcomes on average than their low-income, stably housed peers.”

The mayor has called the housing plan “a central pillar in the battle against inequality.” While many details need to be worked out, the plan holds promise for the thousands of Dasanis who struggle every day to learn, in a city that for too long had seemed to turn its back on them.