About four months after 1.1 million New York City children were forced into online learning, Mayor Bill de Blasio announced on Wednesday that public schools would still not fully reopen in September, saying that classroom attendance would instead be limited to only one to three days a week in an effort to continue to curb the coronavirus outbreak.

The mayor’s release of his plan for the system, by far the nation’s largest, capped weeks of intense debate among elected officials, educators and public health experts over how to bring children back safely to 1,800 public schools.

The decision to opt for only a partial reopening, which is most likely the only way to accommodate students in school buildings while maintaining social distancing, may hinder hundreds of thousands of parents from returning to their pre-pandemic work lives, undermining the recovery of the sputtering local economy.