On Feb. 8, the night before I went to a vigil for Dr. Li Wenliang in New York’s Central Park, one of my friends warned me: “Wear a mask and sunglasses. Don’t show your face. Protect yourself.” I thanked her for her kindness but decided not to wear any “protection.” What danger would I face if I’m just mourning a doctor who had saved countless lives by being a “whistleblower” about the rapidly spreading coronavirus and eventually died because of it?

When I arrived at the vigil, however, I saw that a majority of the people there were wearing masks and a few wore sunglasses, and then I realized my friend was not kidding. You can be in danger by showing up at a gathering that may be viewed as a demonstration of discontent with the Chinese government, even if it’s held in New York, 6,824 miles away from Beijing.

This incident was not isolated from our daily lives. Every Chinese friend I know who lives in the United States uses the messaging platform WeChat to communicate with their families and friends in China, and most of us follow the unspoken protocol of not criticizing the Chinese government while having discussions in WeChat groups, sharing articles or posts in WeChat Moments or even having private conversations with families and friends.

The all-pervasive censorship by WeChat or Chinese authorities has in fact silenced most of us overseas Chinese. There was recently an article on the Dongying City official website praising the efficiency of the internet censorship police, stating that they spend 20 hours every day deleting posts and have the target of deleting any “rumor post” within 30 minutes of its publishing. The article inadvertently stimulated another wave of fury among Chinese internet users, and the original article can no longer be found (though copies are circulating online).

Despite the fact that we reside in a country that protects freedom of speech, we feel too insecure to criticize the Chinese government on a Chinese app. We fear losing connections with our families and friends in China if our WeChat accounts are blocked; we fear potential vengeance by the Chinese government against our families in China; we also fear the possibility of never being able to return to China because of the danger of getting arrested.

Our fear is not baseless. In July 2019, one Chinese student, Luo Daiqing, from the University of Minnesota, was arrested while he was visiting his family in Wuhan during the summer break and sentenced to prison for six months because he had, while in the U.S., tweeted certain cartoon images that were judged by a court in Wuhan to “uglify” President Xi Jinping.

On Aug. 1, the Chinese website Sohu reported that arrests were made in four Chinese cities (Wuhan, Nanjing, Yichang, Dalian) on the same day of people who had posted certain anti-China statements or cartoons while they were living overseas. A passage at the end of the article sends a very clear and intimidating message to overseas Chinese: “Even if you are overseas, think twice before you post anything on the internet. People can get into trouble by just saying certain things. If you violate the relevant Chinese rules by posting on the internet overseas, you will be prosecuted when you return to China!”

Those arrests could be part of an apparent top-down campaign to intimidate overseas Chinese into not exercising their freedoms of speech in other countries.

Over the course of several high-level meetings in China in January and February about managing the coronavirus epidemic, officials — including President Xi — have emphasized the importance of controlling the international community’s media reaction to the outbreak.

Our fear is not just about using Chinese apps.

Our use of YouTube seems to be targeted as well. Since the coronavirus outbreak, Chen Qiushi, a citizen journalist, and Fang Bin, an ordinary businessman in Wuhan, had been posting YouTube videos about what was happening in Wuhan. The video bloggers were attacked with vicious comments, calling them liars and traitors. Now, Chen has been missing since Feb. 6, and Fang has been missing since Feb. 11.

Born and raised in China, I’ve known since I was very young that there are certain topics that can’t be discussed openly in China. Among them are the Cultural Revolution and the Tiananmen Square crackdown. But growing up in the golden years of 1990s and early 2000s, after the Reform and Opening-up by Deng Xiaoping, I have had teachers in high school and professors in college who criticized the Chinese government in certain ways without getting into any trouble.

Those days are now gone. In the past few years, dozens of Chinese professors have been silenced, arrested or exiled because of their criticism of the Chinese government, including my wife’s constitutional law professor at Tsinghua Law School, Xu Zhangrun. What’s more tragic is that some of the professors were reported to the police by their own students. This would have been unimaginable when I was in college, when students like me were eager to learn about the professors’ insights on different political and legal systems, which unavoidably included criticisms of the systems, including that of China. We all then understood the intention behind these discussions was to make our society a better one for ordinary Chinese people.

Another Tsinghua Law School professor, Lao Dongyan, wrote in a recent article: “If criticism is not allowed, then praise is meaningless.” I was lucky to have had mentors who instilled in me the importance of independent thinking and criticism when I studied in China. But now, as I stand in the land of liberty, where freedom rings, I still feel every day the contradiction of freedom of speech and fear of consequences.

Fan Wei is a corporate lawyer in New York and wrote this piece for the Chicago Tribune.