A Hong Kong court sentenced a group of pro-democracy activists to up to 18 months in prison Friday for organizing a massive unauthorized protest in August 2019 that drew an estimated 1.7 million people, AP reports.

Why it matters: Critics say the sentences send the message that even peaceful pro-democracy activism will be severely punished. They mark a continuation of Beijing's overhaul of Hong Kong's political structure, designed to crack down opposition to the Chinese Communist Party.

Context: Pro-democracy activist Jimmy Lai, the 73-year-old founder of Hong Kong's Apple Daily tabloid and an open critic of the party, was arrested and charged with "colluding with foreign forces" in December 2020 under Hong Kong's new national security law imposed by Beijing earlier that year.

• His arrest drew condemnation from Western governments and international human rights groups.
• Lai and others were found guilty earlier in April of organizing and participating in two protests in 2019 that had been banned by police.

The big picture: Also among those sentenced was Martin Lee, an 82-year-old lawyer often referred to as Hong Kong’s “father of democracy,” who received 11 months in prison, according to the New York Times.

Go deeper: With Hong Kong arrests, China outlaws democracy itself