Chinese performance artist and activist Brother Nut, age 39, is using silence to send a message opposing government censorship, particularly with regard to the coronavirus pandemic.

As part of a new project he’s calling #shutupfor30days, Brother Nut kept his mouth closed for 30 days, sealing his lips in different ways—with metal clasps, gloves, and a surgical face mask reading “shut up.” In a reference to China’s widespread blocking of internet content, Brother Nut also wore packing tape with the “404 error” code that comes up when a website can’t be found.

China has been widely criticized for possibly covering up the severity of the COVID-19 pandemic. During the early days of the outbreak, police arrested Chinese doctor Li Wenliang and forced him to confess to “spreading rumors” when he alerted colleagues to the deadly new virus. Li later died of the disease.

“Sometimes I feel my job is similar to that of an NGO or a journalist—seeking to raise awareness of social issues and the moves to counter them,” Brother Nut, who goes by a pseudonym to avoid police retaliation, told Reuters. “If you ask me how an artist should digest unfair treatment, such as violence or censorship, my first reaction is: keep fighting, with art.”

The artist’s work has already attracted negative attention from the government. He was previously detained by police for 10 days.

In 2018, Chinese authorities shut down a Brother Nut exhibition that featured more than 9,000 bottles of Nongfu Spring, a common Chinese brand of water. He had refilled each one with contaminated drinking water from a Chinese village to highlight the dangers of pollution.

The artist also made headlines with a 2015 work, Project Dust, for which he vacuumed smoggy Beijing air for 100 days during a period of particularly poor air quality in the city. Sometimes mistaken for a high-tech street sweeper with his industrial-strength vacuum, Brother Nut took the tiny condensed pollution particles and mixed them with clay to create brick sculptures that represented the negative health effects of air pollution.