SHANGHAI (Reuters) - A court in Shanghai jailed a man for eight years on Friday after he set off an explosive device last year at the city’s Pudong International Airport, injuring at least three travelers and delaying flights.

In a brief statement, the court said that Zhou Xingbo set off the device because his “life was not smooth” and so he took extreme measures to “vent his spleen”, injuring three people. It did not give details. The government initially said five people were injured, including the person who set off the device.

Zhou Xingbo took a beer bottle containing self-made explosive materials out of his backpack and threw it at ticketing counter. After the bottle exploded, he then took out a knife and slashed his own neck, the government said.

Business hub Shanghai is mainland China’s most cosmopolitan city, with a large foreign population, but is generally very safe with major crime unusual.

Explosives are relatively easy to obtain in China though, home to the world’s largest mining and fireworks industries.

A man in a wheelchair detonated a home-made explosive at Beijing’s international airport in 2013, injuring himself in what was an apparent attempt to draw attention to an earlier grievance.

Individual Chinese unable to win redress in disputes have in the past resorted to extreme measures, including bombings, but such incidents are rare amid the tight security at the country’s airports.