Mayor Bill de Blasio declared a state of emergency in New York City Thursday in response to the rapidly developing novel coronavirus pandemic, and he and Governor Andrew Cuomo announced additional measures to combat the spread of the virus.

As of this writing, New York has 328 cases across the state, of which 95 are in New York City. This is an increase of 112 statewide and 53 citywide from Wednesday—meaning that cases in New York City more than doubled overnight. There are at least 1,300 cases nationally.

Cuomo and de Blasio held sequential news conferences announcing their measures, with Cuomo in particular indicating that the situation is even worse than indicated by the number of confirmed cases, which he said “mean nothing” due to lack of tests. Cuomo added that he would not be shocked if the real number were ten times the reported number.

The most significant measure announced by Cuomo was banning all events with more than 500 people. As every Broadway theater holds more than 500 attendees, this means that as of 5 p.m. yesterday, what is arguably New York’s most iconic cultural institution—as well as a significant tourist attraction—is closed until at least April 12. This announcement comes after a Broadway usher was diagnosed with Covid-19, the official name of the disease caused by the novel coronavirus.

Madison Square Garden and the Barclays Center may likewise be closed potentially for months due to the ban.

Locations with a legal occupancy below 500 people have to remain below half their maximum capacity. Among the few exceptions are the schools, hospitals, nursing homes and mass transit, which could well prove to be major sites of transmission of the virus. Similarly, the neighboring states of New Jersey and Connecticut have banned events of more than 250 people.

De Blasio announced limited measures at a subsequent news conference, in addition to announcing the state of emergency itself, including that 10 percent of municipal workers could telecommute and another 20 percent could work staggered schedules to avoid rush hour. He said the coronavirus crisis could go on for another six months.

The mayor also announced that many extracurricular school activities would be canceled, although the schools themselves would remain open.

This is because over 10 percent of New York City public school students are homeless, and the overwhelming majority of them are poor. For many, schools are absolutely necessary for internet access, hot meals, medical care, childcare and other forms of social support.

Nonetheless, there are growing demands to close New York City public schools, including those articulated in an open letter to de Blasio published Thursday by unnamed “Doctors and public health officials working in NYC’s hospitals, jails, clinics, and shelters,” released by New York City Council Members Brad Lander and Ritchie Torres.

These doctors and officials urge “that aggressive measures must be taken now,” including the suspension of classes at public schools, turning them into centers for community aid, as well as guaranteeing up to two weeks of paid sick leave and ensuring “that medical personnel have adequate personal protective equipment.”

Teachers and others are demanding that the schools close as well, with a longtime teacher telling the World Socialist Web Site, “I think the schools should close.” He relayed that there has been no communication from the head of the United Federation of Teachers, and that “[t]here have been no teacher meetings about the coronavirus.”

Almost 200,000 people have signed a petition demanding the closure of the schools, and the Twitter livestream of de Blasio’s state of emergency announcement was dominated by comments demanding the closure of the schools, which has become a major political issue in the city.

Major cultural institutions have announced their closure due to the virus, including Carnegie Hall, the Metropolitan Museum of Art, the Metropolitan Opera, the Whitney Museum of American Art, the Solomon R. Guggenheim Museum, the Frick Collection, the Neue Galerie, the Bronx Museum of the Arts, the American Museum of Natural History, the Museum of Modern Art and the New York Philharmonic.

While health concerns are primarily driving the cancellations, the New York Philharmonic’s music director, Jaap van Zweden, is currently in Amsterdam, and is now affected by the travel ban on Europeans announced by President Donald Trump Wednesday night.

The St. Patrick’s Day Parade has been postponed indefinitely after the organizers spoke with the governor and the mayor, and after other St. Patrick’s Day parades were canceled, such as Boston’s. This is the first time the New York parade has been postponed since it began in 1762.

Many universities in the state have announced that they are moving to all-online instruction, in many cases until the end of the semester. This includes Columbia University and the entire State University of New York (SUNY) and City University of New York (CUNY) systems, with SUNY and CUNY educating almost 700,000 students between them.

The Metropolitan Transportation Authority (MTA) announced Thursday that it is now disinfecting every subway station twice daily, instead of once as before. In addition to the previously announced measure of disinfecting all subway cars and buses every three days, the MTA now also says it is cleaning Long Island Rail Road and Metro-North Railroad trains on the same schedule.

Also on Thursday, the National Guard arrived in New Rochelle, a suburb north of New York City, after Cuomo instituted a 1-mile “containment area” on Tuesday. The containment area is in response to a cluster of Covid-19 cases, now numbering 113 and therefore by far the largest cluster in the United States, connected to a New Rochelle attorney who works in Manhattan and contracted the virus through community spread.

In addition to the New Rochelle cluster, there are dozens of cases on Long Island and a growing number in upstate New York. Western New York reported its first case: a man in Rochester who returned from Italy. Monroe County Public Health Commissioner Dr. Michael Mendoza, in response to the first case in his county and region, suggested canceling gatherings of more than 50 people.

Reflecting broad anxiety among the population, distrust of authorities and a recognition that major measures of some kind need to be implemented, rumors circulated on social media and in workplaces of plans to shut down the subway system and quarantine Manhattan.

The New York City Police Department and de Blasio’s press secretary both issued statements—the former in frantic all-capital letters—denying the rumors.