Demonstrators in Hong Kong have again blocked key roads and government buildings, with police firing tear gas and rubber bullets in response.

On the surface, these protests are about plans that would allow extradition from Hong Kong to mainland China (we've explained those plans - and just why they rankle - here).

But this is not all happening in a vacuum. There's a lot of important context - some of it stretching back decades - that helps explain what is going on.
Hong Kong has a special status...

It's important to remember that Hong Kong is significantly different from other Chinese cities. To understand this, you need to look at its history.

It was a British colony for more than 150 years - part of it, Hong Kong island, was ceded to the UK after a war in 1842. Later, China also leased the rest of Hong Kong - the New Territories - to the British for 99 years.

It became a busy trading port, and its economy took off in the 1950s as it became a manufacturing hub.

The territory was also popular with migrants and dissidents fleeing instability, poverty or persecution in mainland China.

Tear gas and rubber bullets used in Hong Kong
Read more about Hong Kong's history

Then, in the early 1980s, as the deadline for the 99-year-lease approached, Britain and China began talks on the future of Hong Kong - with the communist government in China arguing that all of Hong Kong should be returned to Chinese rule.

The two sides reached a deal in 1984 that would see Hong Kong return to China in 1997, under the principle of "one country, two systems".

This meant that while becoming part of one country with China, Hong Kong would enjoy "a high degree of autonomy, except in foreign and defence affairs" for 50 years.

As a result, Hong Kong has its own legal system and borders, and rights including freedom of assembly and free speech are protected.

For example, it is one of the few places in Chinese territory where people can commemorate the 1989 Tiananmen Square crackdown, where the military opened fire on unarmed protesters in Beijing.
...but things are changing

Hong Kong still enjoys freedoms not seen on mainland China - but critics say they are on the decline.

Rights groups have accused China of meddling in Hong Kong, citing examples such as legal rulings that have disqualified pro-democracy legislators. They've also been concerned by the disappearance of five Hong Kong booksellers, and a tycoon who then turned up in custody in China.

Artists and writers say they are under increased pressure to self-censor - and a Financial Times journalist was barred from entering Hong Kong after he hosted an event that featured an independence activist.

https://www.bbc.com/news/world-asia-china-48607723