One of the most pertinent examples of the Chinese government's strong hand is its strict regulation over the Internet, disallowing citizens to visit unwanted and apparently corruptible sites like Facebook, Twitter and WordPress. So it came as little surprise when various news sites reported yesterday that the Internet in China was acting in less than a free-flowing fashion.

Around mid-day local time on Thursday, Chinese users reported being unable to access previously unbanned foreign sites like Yahoo, Microsoft and Gmail, according to China Tech News. Local sites like Sohu.com and Sina.com remained available to local users.

Meanwhile, outside of China – in countries like the U.S. and Hong Kong – users were denied access to a number of Chinese sites. As the Telegraph's Malcolm Moore noted, China spent the majority of yesterday “walled in” – at least from an Internet perspective.

With a traditionally mum government still running the country, no clear cut reason for the disruptions have been identified, although several rumors have begun to circulate. One option is the 8.5 magnitude earthquake that struck off the coast of Indonesia on Wednesday, possibly damaging the undersea cables that connect China to the rest of the world.

However, sources told Moore that this scenario is rather unlikely – if not impossible – because any damage to the network would have affected domestic sites as well.

Another possibility is that China was toying with its well-publicized, yet never-officially-acknowledged filtering system. “It seems that everyone's best guess is that they were upgrading the Great Firewall and something glitched during the process,” an unnamed official at one of China's Internet companies told The Telegraph. “My own theory is that they were testing the great switch to turn off the Internet.”

Yet another reason for the partial Internet outage could be an attempt by the government to cool the rumor mill surrounding ousted Chongqing city chief Bo Xilai and his wife, who has reportedly been jailed for the alleged murder of a British businessman.

More than 40 websites have been shut down and 210,000 posts have been deleted since Xilai's ousting. In addition, Reuters reported that China's three largest Internet providers have agreed to take measures to stop the spread of Internet rumors.

Whatever the reason for the strange disruption, China's Internet is now back to its former self – available yet censored.