Some parents in Belmont cheered when Massachusetts Education Commissioner Jeffrey Riley required the town and other districts with low COVID-19 infection rates to explain why students had not yet returned to classroom learning.

“Our district should be fighting to get our kids back into school,” said Christine McLaughlin, who has three teenagers.

McLaughlin, a vocal advocate for bringing students back to classrooms, started a petition in August that has drawn more than 600 signatures from parents protesting the Belmont School Committee’s decision to begin the year remotely.

Nearby communities like Winchester and Needham have already brought their students back into classrooms, she noted.

Because of Riley's Sept. 18 letter, Belmont and 15 other communities — including Watertown, West Springfield and Bourne — must explain to the state why they have not returned to in-person or hybrid learning. Some are not happy about it.

In affluent Belmont, school committee chair Andrea Prestwich said the district's decision to conduct comprehensive air-quality tests in the schools forced them to begin the year remotely, but only temporarily.

The state wrongly made it seem like they have not been compliant, she said.

“It’s not like we’re out for the whole year," Prestwich said. "We’re just doing it slowly and making sure our buildings are safe as we go.”

Riley's letter alerted districts that they had 10 days to submit a timeline about their plans for restarting in-person learning. He wrote that as of Sept. 16, the two-week positivity rate for the state was below 1 percent and that local metrics show a low risk of infection (fewer than five cases per 100,000 people) in the communities cited.

“Please note that your response may trigger an audit to assess overall efforts to provide in-person instruction,” he wrote.

West Springfield Mayor Will Reichelt said he also felt annoyed by the letter, calling it unnecessarily punitive.

Both Reichelt and Prestwich said their districts already filed plans with state education officials notifying them about dates for voting on holding in-person learning two days per week. Most hybrid school models require two days a week of in-person learning and three days of remote.

Prestwich said Belmont began air quality testing in late August instead of earlier in the summer because the science around how the virus can linger in the air in aerosolized particles was emerging and the district wanted to play it safe.

The school committee is not a highly trained team of epidemiologists, Prestwich said, so staying on top of scientific developments has its challenges — even though she is an astrophysicist.

But state officials are taking a hard line. Education Secretary James Peyser, Riley's boss, said districts were informed prior to the letter that the state wanted students to go to school in person quickly in communities with low transmission rates.

“To the extent that they ignored that advice or decided to go in a different direction anyway, especially given the very low rates of Covid within their communities, we felt it was important to let them know that we are concerned,” he said.

Peyser said the Department of Elementary and Secondary Education doesn't have the authority to require schools to educate students in person. But if the state believes some districts are not providing enough hours of structured learning, either remotely or in person, the department could take action to investigate.