Shanghai’s biggest taxi company is calling in all cabs with an unlucky four in their licence plate numbers to boost students’ chances in this week’s college entrance exams, the China Daily reported on Monday. The word for “four” in Mandarin and Cantonese sounds like the word for “die” and in Shanghainese has the added connotation of being a loser.

“Lots of parents refuse to take cabs with number plates which they consider unlucky, and we’ve seen many of them get angry at us because we have used them to carry their children in past years,” a Shanghai Dazhong Taxi Co. official was quoted as saying. Parents and children across China do everything they can to maximise their chances of success in the rigorous annual test, which is the ticket to higher education and a fighting chance in the country’s increasingly competitive job market. The high pressure that surrounds the exam has turned cheating into an underground industry.

Police around China had recently cracked 28 cases in which suspects advertised text message exam answers for sale, Xinhua news agency said. “Last year, several people, including college teachers, were convicted of selling test papers of national college English proficiency exams for illegal profits and sentenced to jail terms,” it said. More than 8.6 million students around China would sit for the four-day test this year, the agency said.