Here is a timeline of developments since China imposed national security legislation in Hong Kong this year, making anything Beijing regards as subversion, secession, terrorism or colluding with foreign forces punishable by up to life in prison.

June 30: Beijing unveils details of the national security law, which takes effect just before midnight on the eve of the anniversary of its handover from British to Chinese rule on July 1.

July 1: Police arrest more than 300 people as protesters take to streets. Ten are arrested under the new national security law.

Britain promises to grant those in Hong Kong with British National Overseas (BNO) passports five years of limited stay to work or study as a pathway to citizenship.

July 2: Government says protest slogan "Liberate Hong Kong, Revolution of our times" could constitute subversion.

July 3: United Nations says it is "alarmed" at arrests in Hong Kong under new law.

July 5: Hong Kong's Education Bureau urges schools to review textbooks to make sure they do not violate security law.

First person charged under the new law is denied bail.

Facebook Inc, Google Inc and Twitter Inc say they have suspended processing government requests for user data in Hong Kong.

July 8: New national security office employing mainland agents is set up in a Hong Kong hotel. Protest anthem "Glory to Hong Kong" is banned in schools.

July 14: Beijing's top representative office in Hong Kong warns that primary elections to select democracy candidates for Legislative Council elections in September could violate the national security law.

July 15: President Donald Trump orders an end to Hong Kong's special status under U.S. law. Beijing warns Washington of retaliatory sanctions.

July 17: Taiwanese officials in Hong Kong are told their visas will not be renewed unless they sign a document supporting Beijing's claim to Taiwan under its "one China" policy.

July 20: Britain announces it will suspend its extradition treaty with Hong Kong.

July 28: The University of Hong Kong (HKU) sacks veteran pro-democracy activist Benny Tai from his tenured position as an associate professor of law.

July 29: Police arrest four people under the security law, the first such detentions outside of street protests.

July 30: Hong Kong disqualifies a dozen pro-democracy candidates from running in the September election, citing reasons including collusion with foreign forces and opposition to the new law.

July 31: Chief Executive Carrie Lam postpones the September election, citing a spike in coronavirus cases.

Aug. 7: The United States imposes sanctions on Luo Huining, the head of China's Liaison Office in Hong Kong, Chief Executive Lam and other current and former officials that Washington accuses of curtailing political freedoms in Hong Kong.

Aug. 10: Media tycoon Jimmy Lai is arrested under the national security law, and detained over suspected collusion with foreign forces, as police search the offices of his Apple Daily newspaper.

Aug. 26: The Guangdong Coast Guard arrests 12 people sailing in mainland Chinese waters from Hong Kong to Taiwan where they planned to apply for political asylum. Ten were sentenced on Dec. 30 to between seven months and three years in jail related to illegally crossing the border. Two minors were not charged.

Sept. 6: Police fire rounds of pepper balls at protesters and arrest almost 300 during demonstrations on the day of the postponed legislative elections, to oppose the postponement and the national security law.

Sept. 18: One of 14 foreign judges on Hong Kong's highest court says he has resigned over the national security law.

Oct. 1: Carrie Lam hails the city's return to stability at China National Day celebrations as riot police arrest dozens while patrolling the route of a banned anti-government march.

Nov. 9: The United States imposes sanctions on four more Chinese officials in Hong Kong's governing and security establishment over their alleged role in implementing the national security law.

Nov. 10: Hong Kong says it is suspending extradition agreements and pacts on mutual legal assistance with the Netherlands and Ireland after both countries joined Britain, the United States, Canada, Australia, New Zealand, Germany and Finland in suspending extradition treaties with Hong Kong.

Nov. 11: Hong Kong expels four opposition members from its legislature shortly after Beijing passes a resolution allowing local authorities to expel legislators deemed a threat to national security or not holding allegiance to Hong Kong, without having to go through the courts.

Nov. 12: Remaining 15 opposition members of the 70-seat Legislative Council resign in protest.

Dec. 2: Prominent activist Joshua Wong, 24, jailed for more than 13 months over an unlawful anti-government rally in 2019.

Dec. 7 and 8: Sixteen activists arrested over July's protest and a November university protest, police say.

Jan 6: Over 50 pro-democratic activists arrested on suspicion of breaking the national security law, according to local media, the biggest crackdown to date under the new law. Arrests include well known democratic figures and former lawmakers.