Harbin on Tuesday postponed the launch of its online license plate application system after police discovered that hackers had “paralyzed” the website.

Like many of China’s larger cities, Harbin, capital of Heilongjiang province in China’s far northeast, planned to limit available license plates in order to control the number of vehicles on its notoriously congested roads. The city had developed a new website for this system but discovered that it had been compromised, state broadcaster China Central Television reported Tuesday.

The new website would also limit petty corruption from officials with the power to give out number plates considered lucky.

“I heard we had this online registration system,” local resident Han Tingting told Sixth Tone. “Transport police, the vehicle administration office, and traffic radio publicized the online system every day. People prepared for this number plate selection, but now it’s been suspended.”

The city’s traffic police released a statement acknowledging the breach and saying that the website’s new launch date is uncertain. It did not mention how or why hackers had gained access, but due to the limitations cities place on license plates, they can be highly sought-after commodities.

In Shanghai, for example, people who want to own a car have to enter a monthly online auction. In June, 244,349 people vied for just 10,312 numbers, pushing the average price to nearly 90,000 yuan (about $13,000).

In addition to Harbin, other cities around China have experienced similar hacks into their license plate registration systems. In 2009, a man was sentenced to 14 months in prison for hacking Shanghai’s vehicle registration website, which also led to that system’s suspension.

Last year, police in Zhuhai, a city in southern China’s Guangdong province, arrested a criminal gang who had hacked several such websites around China. The gang had managed to get ahold of license plates with numbers considered auspicious in China, such as six and eight. They had made more than 2 million yuan from selling them to car owners looking for a little extra luck in their lives.

The Ministry of Public Security earlier this year announced a nationwide system for license plates that launched Tuesday in select provinces and cities around China.

Editor: Kevin Schoenmakers.

(Header image: Car owners with license plates stand outside the Department of Motor Vehicles in Nantong, Jiangsu province, Dec. 31, 2012. Xu Congjun/VCG)