A Buddhist woman’s conviction this week on blasphemy charges has alarmed many in Indonesia who were already worried about the erosion of religious pluralism in the world’s largest Muslim-majority country.

Meiliana, a 44-year-old Buddhist from the island of Sumatra, was convicted Tuesday of violating Indonesia’s controversial blasphemy law and sentenced to 18 months in prison. Her crime: complaining about the volume of the Islamic call to prayer blasted by a mosque’s loudspeakers near her home.

Last year, popular former Jakarta governor Basuki Tjahala Purnama, who is a Christian and is commonly known as “Ahok,” was sent to prison for two years under the blasphemy law for allegedly disrespecting the Koran.

Meiliana, who like many Indonesians uses only one name, may appeal the decision against her, though convictions of this type are rarely overturned.

The case has made Meiliana a minor cause celebre among more-liberal Indonesians, and the country’s two largest Muslim organizations have criticized her conviction.

“She did not commit blasphemy. What she did was offer a neighborly complaint, and that is not an insult to Islam,” said Ismail Hasani, a legal expert at the Islamic State University in Jakarta and research director at Setara Institute for Democracy and Peace, which he said would work with other civil society groups to fight Meiliana’s conviction. “More generally, we believe that the blasphemy law itself does more than anything else to limit freedom of religion in Indonesia.”

Indonesia, a multiethnic democracy made up of thousands of islands, officially recognizes six religions as equal under the law and has long been viewed as one of the most tolerant Muslim-majority nations in the world. But developments in the past few years – including Ahok’s conviction, proposed legislation to ban homosexual acts and the rise of Islamist political groups –- have worried supporters of the secular approach.

This month relatively moderate President Joko Widodo stunned his more liberal supporters by announcing that his running mate in his re-election bid next year would be Islamic cleric Ma’ruf Amin. In his role as head of the Indonesian Ulema Council, Amin was influential in the push to jail Ahok, a former close ally of Widodo.

Meiliana’s case has become part of the larger debate over religious pluralism. By Thursday, tens of thousands had signed an online petition asking Widodo to “Free Meiliana (and) uphold tolerance!”

Her case has also sparked discussions about the call to prayer itself and its volume.