More than 660,000 high school students and graduates in South Korea took the state-administered annual college entrance exam on Thursday, the most crucial test seen as a deciding factor in an applicant's choice of college and subsequent career.

A total of 668,522 people applied for the day-long standardized College Scholastic Ability Test, of which about three-quarters were high school students, the ministry said, adding this year's number of test takers dropped by about 4 percent from last year.

The test, administered at 1,191 test centers across the country, will run for about nine hours through 5:35 p.m., including lunch and breaks, and consists of five sections -- Korean language, mathematics, English, social and natural sciences, and a second foreign language -- the ministry said.

As part of efforts to ensure that the most crucial test in a student's life was executed without any glitches, the government imposed various traffic control and anti-noise measures.

The subway ran more frequently in the morning rush hour, and traffic was banned within 200 meters of test centers, while government offices and enterprises in nearby areas delayed their opening by one hour to 10 a.m., according to the government.

Police operated a temporary call center to serve students wishing to ride in a patrol car or on the back of a motorcycle to reach their test centers, while dispatching more than 13,000 officials across the country for test takers' safety and convenience, the National Police Agency said.

Flight landings and takeoffs will be banned for 13 minutes during a listening test for Korean in the morning and for 20 minutes for the English listening exam in the afternoon, according to the education ministry. 

Test takers are banned from carrying to their seats electronic devices, including mobile phones, digital cameras, MP3 players and electronic calculators, for concerns they might be used for cheating, the ministry said.

Students will be individually notified of their test results by Nov. 28, it added. (Yonhap News)