- China imposed a sweeping national security law on Hong Kong in June 2020 that punishes what authorities broadly refer to as secession, subversion, terrorism and collusion with foreign forces with up to life in prison.
Government officials in Beijing and Hong Kong said the law would target only a small number of "troublemakers" who threaten national security, and that the rights and freedoms of ordinary Hong Kong people would be protected.
Critics say it is being used to crush dissent in the global financial hub, an assertion Beijing rejects.
HOW FAR DOES THE LAW GO?
The reach of the law has stunned some diplomats, lawyers, activists and legal scholars. The legislation provides for more active state management and oversight of foreign groups, organisations and media based in Hong Kong, a former British colony that has been China's freest and most international city.
The law stipulates that mainland agents, who are now officially based in the city for the first time, cannot be detained or inspected by local authorities while carrying out their duties.
Most defendants have been denied bail and one was denied trial by jury.
It also allows Hong Kong's chief executive to appoint judges for national security cases - a move lawyers' groups have said imperils the city's rule-of-law traditions.
The legislation also allows mainland courts to hear serious and complex Hong Kong cases in certain situations, including those allegedly involving collusion with foreign forces - a significant change that has alarmed some in the city.
Under the law, any Hong Kong residents running for election or working for the government must swear allegiance to the city and its mini-constitution, the Basic Law.
WHAT HAS BEEN THE IMPACT?
More than 100 people have been arrested under the national security law, with high-profile democracy and independence activists among the first to be detained.
A dozen pro-democracy candidates were disqualified from running in a since-postponed election last September, with authorities citing reasons such as collusion with foreign forces and opposition to the law.
Some diplomats, activists and human rights groups have expressed deepening concerns over the erosion of freedoms.
Fourteen Asian and Western diplomats told Reuters said they were alarmed at attempts by Hong Kong prosecutors to treat links between local politicians and foreign envoys as potential national security threats.
WHAT COMES NEXT?
In a city that has had strong media, artistic and religious traditions that are protected to a far greater degree than those on the Communist Party-ruled mainland, fear is building the law will increasingly crush those freedoms.
Scrutiny is also intensifying over Hong Kong's vaunted judiciary and rule of law, long seen as crucial to the city's standing as a global financial hub, as national security cases go to trial.