School is back in session for NYU students in Shanghai, China, but one subject that won’t be on the syllabus is pro-democracy protests sweeping Hong Kong.

NYU faculty in China and New York say the issue is a third rail, particularly after the international imbroglio caused by Houston Rockets general manager Daryl Morey’s tweet in support of the demonstrators.

“Everyone is under a bit of a cloud of fear,” one faculty member who teaches at NYU’s sprawling 600,000-square-foot Shanghai campus told The Post. “We don’t walk around trembling like rodents, but there is a general idea that there are certain topics you don’t discuss.

“Most of us are on guard about what we say even when we talk about the weather,” the faculty member continued, saying that student protests at the Shanghai campus would be unthinkable.

“It would draw a lot of negative attention. It is everything that NYU Shanghai doesn’t want,” the staffer added. “We all learn over time how to self-censor.”

Since classes officially began on Sept. 2, both the Facebook and Twitter account for NYU Shanghai have made no mention of the protests making international headlines for months.

While students and teachers discuss the matter in private, the only known official airing was a panel organized by senior professor Jian Chen. Chen told The Post that the panel had been “off the record” and refused to disclose what was discussed.

Multiple students and faculty on the Shanghai campus also declined to discuss the issue with The Post.

NYU in Shanghai opened to much fanfare in August 2013. The project is a joint venture with Shanghai’s East China Normal University, but the Chinese Communist party looms over it.

In addition to familiar items in the NYU curriculum like “Central Problems in Philosophy” or “Multivariable Calculus,” Chinese students who attend the school are also required by the government to take classes like “Mao Zedong Thought” and “Introduction to the Communist Party of China” during winter break off campus.

Yet in a 2018 policy handbook, former NYU-Shanghai Dean of Students Charlene Visconti trumpeted the schools’ commitment to liberal values.

“The University is a community where the means of seeking to establish truth are open discussion and free discourse. It thrives on debate and dissent, which must be protected as a matter of academic freedom within the University,” she said.

The incoming class of 2023 is comprised of 434 students, of which 220 come from China and 126 from the U.S. The total student body is about 1,300.

Rebecca Karl, who teaches subjects on modern China at NYU’s Washington Square campus told The Post she did not have confidence that the university would go to bat for students or faculty in Shanghai if they spoke out for Hong Kong.

“I do not trust my university to do the right thing,” Karl told The Post. “I am not confident they would actually make a real stand here. They have too much at stake.”

In May NYU officially broke ground on a 1.2 million-square-foot expansion of the Shanghai campus. The construction, which is expected to be completed in 2022, will double classroom space and allow NYU to take in 4,000 more graduate and undergraduate students, according to a press release.

Karl says she is “persona non grata” at the NYU Shanghai campus because of her criticism and has been “repeatedly told … there is no space for me … even as they invite and encourage many of my other colleagues to go out there and teach.” Karl told The Post she has faced pressure from multiple fellow professors in New York not to organize a panel on the Hong Kong protests this semester out of concern that it would “hurt the feelings of my colleagues in Shanghai.”

“I am still going to go forward,” Karl said — though the overall response to Hong Kong protests on campus has been muted.

“We believe our goals as a cultural organization are best served by remaining politically neutral,” NYU’s Hong Kong student association told The Post. “Discussing politics may detract from our overarching goal of promoting Hong Kong culture.”

NYU spokesman John Beckman said the Hong Kong panel in Shanghai was “well attended by students and faculty,” but conceded that the school could not necessarily protect protesting students who run afoul of the Communist party.

“Our students are accustomed to engaging with the larger society and understand that when they are outside a university setting, a university doesn’t have any special authority to immunize its students from harm or jeopardy, nor does being a university student confer a special invulnerability,” he said. “When our students do get into trouble, we act to help them.”