S. Korea holds national college entrance exam [PHOTOS]

Test-takers wait for the beginning of the College Scholastic Aptitude Test (CSAT) at Namsan High School in Daegu, Thursday. Yonhap

South Korea held the annual state-administered college entrance exam on Thursday with roughly half a million applicants sitting for the high-stakes test that some claim will determine their future.

The College Scholastic Aptitude Test (CSAT), also known as "suneung," began at 8:40 a.m. at 1,185 exam venues across the nation, according to the education ministry.

The marathon exam, which covers five test subjects, including Korean, math and English, is scheduled to finish at 5:40 p.m.

A mobile metal detector to prevent cheating using hidden communication devices at Ewha Girls' Foreign Language High School in Seoul, Thursday. Yonhap

Police stand guard at Ewha Girls' Foreign Language High School in Seoul, Thursday. Yonhap

Sung Ki-sun, President of the Korea Institute for Curriculum and Evaluation, speaks about this year's CSAT at the Ministry of Education in Seoul, Thursday. Yonhap

A total of 548,734 applicants were expected to sit for this year's exam, with 394,024 of them high school students. The number of high school student applicants is the lowest since 1993.

The CSAT, held only once a year, is considered critical in Asia's fourth-largest economy. Parents accompany their children to schools and pray for them at churches and temples.

It is also considered a national event, with working hours at public offices delayed by an hour to 10 a.m. to prevent traffic congestion for applicants going to test venues. The local stock and currency markets also open an hour later than usual.

Flight schedules will also be affected for 35 minutes from 1:05 p.m. to 1:40 p.m., when English listening tests will take place.

This year's test results are scheduled to be released on Dec. 4. (Yonhap)