Nguyễn Văn Hoá, 22, rose to prominence after a toxic waste spill from a steel mill built by Taiwan’s Formosa Plastics Corp’s Vietnam unit that polluted more than 200 kilometres (125 miles) of coast, sparking rare protests in the Communist Party-ruled country.

Despite sweeping economic reforms and growing openness to social change, including gay, lesbian, and transgender rights, Vietnam retains tight media censorship, and its government does not tolerate criticism.

In recent months, authorities have stepped up measures to silence critics whose voices on various issues have been amplified by social media in a country that is among Facebook’s top 10 by number of users.

The people’s court in Hà Tĩnh province said on its website Hoá had been found guilty of propaganda against the state. It said Hoá produced videos to call for protests after the spill.

Neither Hoá nor any legal or family representatives were available for comment.

Hoá was arrested and prosecuted in April for publishing anti-government content.

The Formosa incident, one of Vietnam’s worst environmental disasters, is a sensitive topic for the government, as it involves political stability, environmental protection, and foreign investment, all of which have an impact on economic growth.

The government has said it will prosecute identified Formosa protesters for “causing public disorder”.

Another critic of the steel mill spill, Nguyễn Ngọc Như Quỳnh, known as “Mẹ Nấm” (Mother Mushroom), was given a 10-year jail term for publishing propaganda against the state.

A prominent rights lawyer who has represented Quỳnh said on Monday the Bar Federation in Phú Yên province had revoked his license to practice.

“The government does not want me to work as a lawyer anymore because I have been defending poor people, people who were unjustly charged … cases that are sensitive in Vietnam,” the lawyer, Võ An Đôn, told Reuters.

Đôn said he would not be able to defend Quỳnh at her appeal hearing.