Hong Kong (CNN) Students and lecturers at Hong Kong's most prestigious university returned from summer break this month to a very different institution.
The Democracy Wall at the University of Hong Kong (better known as HKU) -- a pinboard where students once shared political thoughts -- is gone. The student union, which once advocated for students, is all but defunct, with four of its members facing charges of advocating terrorism.
Although many students and academics were happy to be back on campus -- many for the first time since the start of the pandemic -- a political chill hangs over the university that some staff say is influencing how they teach.
While the Hong Kong government told CNN the city's universities "continue to enjoy academic freedom," four current HKU staff who spoke with CNN on condition of anonymity said they are more cautious about what they say in class, afraid that their own students could report them to authorities.
The self-censorship began after June last year when Beijing imposed a controversial and sweeping national security law on the city. Since then, more than 140 people have been arrested under the law, including activists, journalists, politicians and educators, and, of those, 85 have been charged.
HKU -- the city's highest-ranked university with more than 30,000 students -- can be considered a microcosm of Hong Kong. Some HKU staff say a climate of fear and uncertainty surrounds what constitutes a breach of the law. And they warn that, like the city itself, the freedoms and rights that once set the university apart from those in mainland China are fast in decline.
"Academic freedom has been eroded. Freedom of speech has been eroded in this university," said one university lecturer, who asked to be referred to by the pseudonym Gordon as they still work at the university. "To pretend that it hasn't is ignoring reality."
The creeping changes risk jeopardizing HKU's status as a world-class institution, some faculty members say, by undermining its efforts to attract top staff and students -- threatening the future of one of the city's most prominent bastions of free speech.
HKU students arrived on campus this month wearing face masks -- a requirement in the city to protect against Covid-19. Almost two years ago, they wore face coverings for a very different reason.
In November 2019, students concealed their identity with masks as they barricaded stairways of the university's campus with couches and tables. Together, they amassed slingshots and Molotov cocktails, turning their university into a fortress against riot police who swarmed outside, armed with tear gas.
At the time, the city was months into a pro-democracy movement that had seen angry Hong Kongers -- many of them students -- face off in street battles against police.
The political situation unfolding both on and off campus frequently crept into classroom discussions -- some professors even referred to the protests as examples in their classes.
Some lecturers publicly supported student demonstrators. The day students turned HKU into a fortress, professors braved the tense face off to negotiate with police. Throughout the protests, staff helped students when they got arrested and provided mental health support, according to students and faculty.
Those protests were brought to a sudden end by pandemic restrictions -- and by June 2020, an increasingly frustrated Beijing had found a more permanent solution: a national security law in Hong Kong.
The law established the crimes of secession, subversion, terrorism and collusion with foreign countries or "external elements." Some crimes carried a maximum penalty of life in prison. Although the law was vague and wide-ranging, authorities initially said the law would only target an extremely small minority of offenders.
"The national security law is a crucial step to ending chaos and violence that has occurred over the past few months," Hong Kong's leader Carrie Lam said, as the law came into force last June. "It's a law that has been introduced to keep Hong Kong safe." In a statement to CNN, the Hong Kong government said "law-abiding people will not unwittingly violate the law."
But in the year since it was imposed, a pro-democracy newspaper closed down and nearly all of the city's leading pro-democracy figures have been either jailed or fled overseas. Protests, which once took place almost every week, have stopped -- and while authorities have said that is due to Covid restrictions, others see it as a way to suppress dissent.
And at HKU, once a beacon for freedom of expression and thought, some say it has already had a chilling effect.
Sarah Cook, Freedom House's research director for China, Hong Kong and Taiwan, said political discussion at Hong Kong universities was once as free as at Western institutions. The university's openness had been "gutted ... almost overnight," she said.
A Hong Kong government spokesperson said universities continued to enjoy academic freedom, but also had the responsibility to make sure their operation complied with the law.
HKU said it continued to uphold the principles of "academic freedom and institutional autonomy."
"There are no boundaries to research and studies provided that they are within the law," a HKU spokesperson said.
HKU lecturer Amy, who isn't using her real name for fear of repercussions, says she has become more anxious about covering certain topics since the national security law was imposed. She increasingly feels as if her classroom is becoming isolated from the real world.
Three other current academics CNN spoke to for this story said they too were cautious over what they said for fear of running afoul of the national security law.
On campus, rumors circulate among professors and students that a student who got a grade they didn't like reported their lecturer to the National Security Hotline, set up so the public can inform authorities about breaches of the national security law, according to two lecturers. The police did not confirm these reports, although a spokesperson said the hotline had received more than 100,000 pieces of information since it was launched in November 2020.
Rumors like this only add to the fear and chill that have swept over HKU.
When HKU switched to remote learning during the pandemic, two professors told CNN they refused to upload recordings of their lectures as they were concerned that any off-hand comments made in class could be used as evidence against them.
Amy said the university's leaders used "double speak" that only added to the confusion.
"The senior management of the university has insisted that we still have academic freedom, and that we should not self-censor. But then in the next sentence, they'll tell us to be careful and not to break the law," said one member of staff, who asked to be known as Mary.
The Faculty of Arts held a meeting last year with a member of the university's senior management team to ask for more specific guidelines on how the national security law would affect what they could write and study, according to two people who were present.
During that meeting, staff asked whether they could still teach about topics such as democracy in Hong Kong, Amy said. They were told they would not have to worry, if what they were saying was academic. They were also told "not to incite students," although it was not made clear what would be considered incitement, she said.
"I have found myself sometimes saying innocent things that sound like an incitement that then I have to turn around and make a joke that I'm not inciting people," she added.
Professors say this vague advice has left them unsure what could see them reported to police.
As students enjoyed their summer break, a sign of what the national security law means for the university was unfolding on campus.
National security police officers raided HKU's student union on July 16, removing evidence as onlookers and media peered through the glass doors outside.
For more than 100 years -- almost as long as the university has existed -- the association represented students on campus. Now, it was being targeted by police for giving some a voice.
On July 7, the student union had passed a motion expressing its deep sadness and appreciation for the "sacrifice for Hong Kong" of a man who had killed himself shortly after stabbing and seriously injuring a police officer in a busy shopping street. In politically charged Hong Kong, where months of protests led many to see the police as the enemy, a minority saw the attacker as a martyr.
Authorities characterized the attack as "terrorism," and police quickly branded union leaders as "messengers of terrorism."
Two days after passing the motion, the student union withdrew it -- but it was too late. The city's leader Lam said she was "ashamed" of the university.
HKU management took action. They said they no longer recognized the union, meaning other services funded by the union -- such as Campus TV -- face uncertainty over how they will operate.
HKU said the situation would not affect the "continued commitment of the University to facilitate and support extra-curricular activities on campus." Hong Kong police said 32 students attended that meeting.
The HKU council said it would "until further notice and subject to review" ban all students who attended the meeting from campus and refuse them access to any university resources. These students' presence on campus "would pose serious legal and reputational risks to the University and have negative impact on its other members," the HKU council said in a statement.
An email seen by CNN which was sent to some students in August asks them to indicate whether they attended the July 7 meeting, whether they proposed or seconded the motion, and how they voted on the motion.
And on August 18, four members, ages 18 to 20, were arrested and later charged with advocating terrorism, which carries a maximum penalty of 10 years in prison.
Some faculty members agreed the student union's motion had been in poor taste -- but they disagreed with the decision to bar the union from campus and prosecute the students. HKU law lecturer Eric Cheung resigned from his position on the university board over the decision to bar the students from campus. "I feel very sad when a university doesn't nurture students and help them correct their mistakes," he said, according to broadcaster RTHK.
Seven members of HKU's 60-member court, which oversees the university and is headed by the city's leader Lam, issued an open letter to the university council, asking them to withdraw the decision to bar members from campus and claiming the university had stripped students of their right to education. The ban remains in place. Lam was not one of the seven signatories.
"They're trying to shut down all student political activity and campus political speech. As much as possible, they want to eliminate any student organization that might have political content or engage in political activity," said Chris Fraser, a professor who left HKU for the University of Toronto in July this year.
One fourth-year government and law student at HKU, who was active in the student union in the past, said after the arrests, he and his friends removed everything in their dorm rooms they thought could breach the national security law.
"I think all students are sad ... that normal students are deeply affected by the incident," he said.
Some faculty staff worry that this latest incident may only worsen the chill felt over the university.
"I think that it's going to have a serious effect on classroom, debate and discussion and also just open discussion on campus," said Mary.
"Because by making an example out of a student union, I think it's going to deter students from feeling that they're safe, having political discussions, or breathing into more general discussions on campus," she said.
Not all students feel the same way -- one 25-year-old master's student at HKU who is from mainland China said the national security law didn't necessarily make him feel safer, but at least it prevented protests. "(The protests) were like a strong medicine that suppresses the symptom but also hurts the body itself."
For years, HKU has been one of the most highly ranked universities in Asia, and a place renowned for political discussion. It counted top political leaders among its alumni, including Hong Kong's current leader Lam and Sun Yat-sen, who helped overthrow the Qing dynasty to found the Republic of China.
In 1923, when Sun was asked where his revolutionary ideas came from during a visit to his alma mater, he responded: "I got my idea in this very place; in the colony of Hong Kong."
Today, his revolutionary zeal would likely breach the national security law.
For onlookers, that raises questions over the future of the university -- whether it can still maintain its international standing as freedoms grow more restricted, and what this means for the future of the former political hub.
HKU did not provide details of whether application numbers had dropped since the NSL was passed. The government, meanwhile, insists the national security law isn't hurting universities.
"With the restoration of law and order and a stable environment in Hong Kong, our universities can refocus on research and academic development, strive for academic excellence, and seize the unprecedented opportunities presented by the technological advancement and development of our country and the region, and in doing so continue to enhance our position as the regional education hub and our ability to attract international talent," a government spokesperson said.
And for now, HKU's rankings have not tumbled -- it's still placed 22nd in the world in the most recent QS World University Rankings. But the rankings are based on five years' worth of data, meaning that any effect on its international reputation since June 2020 is unlikely to be reflected for another few years, according to QS rankings spokesman Jack Moran.
A former student who graduated last year and who asked not to be named described a degree from HKU as a fine wine -- one from 1995 is great, one from 2020 is not.
Gordon, a current member of faculty, says he was warned by a headhunter to leave Hong Kong as fast as possible. "The longer you stay, the more it looks like you're kind of complicit with the system. And you'll be tarred with it," he recalled the headhunter saying.
At the heart of the fear is that Hong Kong University becomes more like institutions on the mainland.
"Until the national security law, it was night and day between what it's like being at a university in China versus a university in Hong Kong," Freedom House's Cook said.
Traditionally, Hong Kong has embraced academic freedom, dialogue and debate -- all qualities that set it apart from mainland China. Academics could produce research critical of the government, and students and faculty were able to share different views without fear of repercussions.
But now, people who have dedicated their lives to making Hong Kong University a world-class institution think Beijing and the Hong Kong government don't care about academic freedoms, Cook said.
"The universities really represent that more liberal culture that is such a big part of Hong Kong's identity as a city, and so different from what the Communist Party has imposed in mainland China," she said. "There's a reason why they're going for the core artery, that they're moving into what is at the heart of so much of Hong Kong."
"I don't think that there's any way to decouple academic and politics," Mary said. "I think to suggest that you can cleanse it of politics is naive, or at worst, misleading."
That in turn would lead to a major brain drain, as students went elsewhere, and universities struggled to recruit staff, even for academic subjects that didn't touch on sensitive topics, she said.
A current member of faculty, who asked to be identified as Helena, said every time one of her students gets accepted into an overseas post-graduate program, her heart feels "a little lighter."
"Although I'm sad that Hong Kong is losing that person, I understand they're going to be free and safe," she said.
Every day, Helena wonders what her limits are, and what would make her no longer continue to work at the university. "We have to kind of grapple with 'how long are we useful? Or do we become kind of, you know, just an instrument?'"