Hong Kong's airport canceled all flights on Monday as protests raged. Here's why.

Elizabeth Lawrence

Hong Kong International Airport shut down all flights after thousands of pro-democracy protesters flooded the airport's main terminal Monday afternoon. 

The airport said in a statement that operations have been "seriously disrupted as a result of the public assembly at the airport today.”

The demonstration is the latest in a series of mass protests spanning two months. Hong Kong activists are calling for more autonomy from Beijing and an independent inquiry into police behavior.

Here's what we know about the unrest in Hong Kong. 

Protesters occupy the Hong Kong International Airport during a demonstration on Aug. 12, 2019.

When and why did the protests start? 

The tension was sparked by a since-shelved extradition bill, which would have allowed some suspects to be sent for trial in mainland China. Opponents believed the bill would expand Beijing's control on the bustling international hub. 

Hong Kong was a British colony until 1997, when China absorbed Hong Kong in a handover. Since then, Hong Kong operates under a "one country, two systems" framework that was supposed to allow the territory to retain its own social, legal and political systems for 50 years. 

Many Hongkongers have concerns over Beijing asserting its control and believe that Chief Executive Carrie Lam, who originally introduced the extradition legislation, must resign.

The protests kicked off on June 9 as hundreds of thousands peacefully took to the streets until a group stormed the government headquarters, where police responded with batons and pepper spray. Since then, the conflict has intensified significantly into violence between protesters and police. 

Lau, a flight attendant protesting at the airport on his day off, said protesters' outrage stems from police's forceful tactics. He gave only his surname to avoid repercussions from his employer. 

“The police have told a lot of lies to Hong Kong people," Lau said. "We cannot believe them anymore. We have to come here to protest."

Airport shut down: Hong Kong airport shuts down amid pro-democracy protest

How have tensions escalated?

Though Lam suspended the bill on June 15 and called it "dead" in a press conference, protests kept growing, eventually turning into a full-blown democracy movement. The activists' demands include Lam's resignation, democratic elections for her successor and investigations into police force. 

In Beijing, the Cabinet’s Hong Kong and Macao Affairs Office said the protests were "beginning to show the sprouts of terrorism," and serve as an "existential threat" to the residents of Hong Kong. Beijing officials could use the growing unrest to crack down on Hong Kong. 

Protesters have been subject to aggressive tactics on the part of riot police. One young woman was hit in the eye with a rubber bullet by Hong Kong police during a protest. Activist leader Joshua Wong tweeted a picture of her face covered in blood, which has since been widely circulated. 

"I am not sure whether her right eye will turn blind or not but it is totally insane and terrible," Wong tweeted. "US should not export tear gas and rubber bullet to HK Police anymore."

At the airport protest Monday, protesters used the slogan "an eye for an eye," according to South China Morning Post

Police have also reported injuries, including eye irritation from laser pointers and burns from gasoline bombs. During protests over the weekend at the airport, protesters tossed bricks at officers. 

More: Protesters storm Hong Kong legislative chamber; police fire tear gas to break siege

What's next for travelers at the airport? 

For now, more than 100 flights are grounded. The airport is one of the busiest in the world, as Hong Kong is a haven for international business. Travelers from around the world are stranded and confused. 

CNN reported that one girl traveling by herself needed to get foreign currency but found the exchange desk closed. She told CNN she had no idea how to exit the airport. 

Some travelers have been offered free Airport Express train rides to the city, according to SCMP. Bus services are now back to normal. 

The numbers of protesters have dwindled with only a few hundred protesters remaining, SCMP reported. The Airport Authority released a statement saying it hoped to continue flights beginning 6 a.m. Tuesday but told passengers not to arrive unless their flights are confirmed. 

"The AA will work closely with its business partners with a view to gradually resume normal airport operations as soon as possible," authorities said.

Contributing: Associated Press

This article originally appeared on USA TODAY: Hong Kong protests shut down airport