More than half a million people in South Korea sat for the country’s gruelling university entrance exam on Thursday as police mobilised to ensure they made it to the test sites on time and all flights were halted for half an hour.

The number sitting the test, essential to secure a place at the country's top universities, was the highest in seven years. Most of the candidates were born in 2007 when there was a surge in births because it was considered an auspicious time to have a baby.

Flights at all airports, including Incheon International Airport, were banned from landing or takeoff between 1:05 pm (0405 GMT) and 1:40 pm to ensure there was no disturbance while the students sat for the listening comprehension section of the English test.

The decision affected 140 flights, including 65 international arrivals and departures. Flight trackers showed aircraft circling near airports as the Transport Ministry restricted aircraft from altitudes below 3,000 meters (9843 ft).

Financial markets and offices opened an hour later than usual to ensure test candidates arrived on time for the nine-hour exam that is seen as crucial for success in the hyper-competitive society.

"This exam has been a goal for nearly 20 years and also a new beginning," said Yeseon Kim, who was waiting outside a test site where her daughter was sitting the exam.

A total of 554,174 people registered this year, up 6% from last year and the highest since 2019. Some 496,000 babies were born in 2007 in a jump that paused a steady decline since the mid-1990s.

South Korea is one of the world's fastest-ageing societies, although its birthrate rose to 0.75 in 2024.