The closure of Hong Kong international airport has shone a fresh global spotlight on the city’s protest movement.

The airport was forced to cancel all remaining passenger flights on Monday – more than 100 – after thousands of demonstrators flooded into the main terminal during the afternoon. The disruption will be felt worldwide, with cancellations including long-haul departures to the US, Australia and the UK.

Hong Kong international serves over 220 destinations, the bulk of which are Asia-Pacific, the most frequent flights being to mainland China, primarily Beijing and Shanghai. But it is a significant hub for the rest of the globe: one in seven arrivals are from Europe and the US. It is the base of Cathay Pacific, which partners and codeshares with airlines including British Airways, American Airlines and Qantas.

Hong Kong is also hugely important for cargo, funnelling more freight by volume, about 5m tonnes in 2018, than any other airport. Air freighters were continuing to take off on Monday night, but a large proportion of cargo is normally carried in the hold of passenger planes.

According to a study by the International Air Transport Association, the aviation sector dependent on the airport added £27bn to Hong Kong’s GDP in 2014. It roughly matches London Heathrow in size, operating on two runways and in the process of constructing a third, serving 75 million passengers in 2018 and employing 73,000 staff.

Facebook Twitter Pinterest A Cathay Pacific jet prepares to land at Hong Kong International airport. Photograph: Jérôme Favre/EPA

Built on the island of Chek Lap Kok and land reclaimed from the sea around it, the airport opened in 1998, soon after the transfer of sovereignty from Britain to China. It replaced the notorious airport at Kai Tak, whose flight paths through the built-up island’s mountains and skyscrapers were legendary among pilots and a source of considerable noise disturbance to inhabitants. The new £17bn airport, constructed by British engineers, allowed planes to land 24 hours a day – and inspired the idea of a Thames estuary airport, instead of an expanded Heathrow, that was championed by Boris Johnson when London mayor.

Monday’s closure is the biggest blow struck on the third occasion that the protests have crossed the water to the airport. Thousands of demonstrators held a sit-in protest to raise international travellers’ awareness in late July – a protest joined by some airline staff, attracting the ire of Beijing. Last week, as part of a strike across Hong Kong, more than 200 flights were cancelled. Cathay Pacific, drawn in to a balancing act between angry staff and warding off Chinese government threats, saw its share price slide by another 5% on Monday, down to its lowest value in a decade.