Beijing: Political censorship in this authoritarian state has long been heavy-handed. But for years, the Communist Party has tolerated a creeping liberalization in popular culture, tacitly allowing everything from popular knockoffs of "American Idol"-style talent shows to freewheeling microblogs that let media groups prosper and let people blow off steam. Now, the party appears to be saying "enough." Whether spooked by popular uprisings worldwide, a coming leadership transition at home or their own citizens' increasingly provocative tastes, Communist leaders are proposing new limits on media and Internet freedoms that include some of the most restrictive measures in years. The most striking instance occurred Tuesday, when the State Administration of Radio, Film and Television ordered 34 major regional television stations to limit themselves to no more than two 90-minute entertainment shows each per week, and collectively 10 nationwide. They are also being ordered to broadcast two hours of state-approved news every evening and to disregard audience ratings in their programming decisions. The ministry said the measures, to go into effect on Jan. 1, were aimed at rooting out "excessive entertainment and vulgar tendencies." The restrictions arrived as party leaders signalled new curbs on China's short-message, Twitter-like microblogs, an Internet sensation that has mushroomed in less than two years into a major - and difficult to control - source of whistle-blowing. Microbloggers, some of whom have attracted millions of followers, have been exposing scandals and official malfeasance, including an attempted cover-up of a recent high-speed rail accident, with astonishing speed and popularity. On Wednesday, the Communist Party's Central Committee called in a report on its annual meeting for an "Internet management system" that would strictly regulate social network and instant-message systems, and punish those who spread "harmful information." The focus of the meeting, held this month, was on culture and ideology. Analysts and employees inside the private companies that manage the microblogs say party officials are pressing for increasingly strict and swift censorship of unapproved opinions. Perhaps most telling, the authorities are discussing requiring microbloggers to register accounts with their real names and identification numbers instead of the anonymous handles now in wide use. Although China's most famous bloggers tend to use their own names, requiring everyone to do so would make online whistle-blowing and criticism of officialdom - two public services not easily duplicated elsewhere - considerably riskier. It would "definitely be harmful to free speech," said one microblog editor who refused to be named for fear of reprisal. This newly buttoned-down approach coincides with a planned shift in the top leadership of the ruling party and government, an intricate process that will last for the next year. During such a period, tolerance for outspokenness outside official channels tends to shrink, and bureaucrats eager for promotion show their conservative stripes. The crackdown also follows popular uprisings across the Middle East that appear to have given China's leaders pause regarding their own hold on absolute power. In the view of some, it also tracks the influence in China's ruling hierarchy of hard-liners like Zhou Yongkang, the public security chief who helped preside over the suppression of riots by ethnic Uighurs in western China's Xinjiang region. On Tuesday, Xinhua, the state news agency, reported that Mr. Zhou was urging authorities "to solve problems regarding social integrity, morality and Internet management" and that he had called for "the early introduction of laws and regulations on the management of the Internet," among other things. Nobody outside China's closeted leadership knows the true reason for the manoeuvres, beyond a general and intangible sense of uneasiness over the degree to which freer speech is taking root here. The microblogs, or weibos, are perhaps the prime example. In the last year, weibos have become the forum of choice for Chinese to pass on news and gossip about scandals involving government and the elite. The two largest, run by the privately held Sina Corporation and Tencent Holdings, each count more than 200 million registered users. In the face of official censorship, their weibos are filled with salacious tales of official malfeasance, such as a July frenzy - photographs included - over a Yunnan Province city official's sex orgy. Industry insiders say the principal weibo (pronounced way-bwah) regulators, based in Beijing and the Shenzhen Communist Party Internet offices, have been assailed by government leaders elsewhere for allowing the scandals to spread online unchecked. In fact, the government could easily shut down microblogs. Officials disconnected the entire Internet in Xinjiang for 10 months after the ethnic riots there in 2009. But their growing popularity makes that highly unlikely. The number of users has quadrupled in a single year. Song Jianwu, dean of the school of journalism and communication at China University of Political Science and Law, said Chinese leaders accepted the need for such outlets for expression. But in the case of weibos, he added, "they are also concerned that this safety valve could turn into an explosive device." He said the government might gradually require more and more users to register under their real names, while demanding that operators monitor posts more closely. "I think they will do it in a step-by-step fashion," he said. "We hope and we have suggested that they will do it in manner that is not antagonistic." Some changes are already evident. Besides the in-house monitors who already scan posts for forbidden topics, operators in recent months have bolstered "rumour refutal" departments, staffed by editors, to investigate and knock down information deemed false. Top officials, including Liu Qi, the party secretary of Beijing, have held publicized visits to microblog companies, sometimes accompanied by popular microbloggers, in which he urged people to uphold social order and the proper ideology - and implying that their own status in official eyes would depend on their cooperation. State restrictions on television are murkier. The rules ostensibly apply to CCTV-1, the general programming channel of Central China Television, but not to CCTV-3, which specializes in arts and entertainment, according to a report in the English-language edition of Global Times, an official newspaper. Many people in the industry have interpreted the decree and earlier measures by central officials as attempts to bolster the ratings of CCTV against the onslaught of entertainment shows produced by satellite stations, which have been wildly successful. Last year, officials told producers of "If You Are the One," a popular dating show on Jiangsu Satellite Television, to tone down the program. Last month, the authorities suspended a talent show on Hunan Satellite Television, "Super Girl," for exceeding a broadcast time limit. Many industry observers said the show may have been offensive for other reasons, including prompting home viewers to show support for their favourite contestants through cellphone texting, an action akin to voting. The shutdown of "Super Girl" was taken as a warning throughout the television industry and presaged the new rules. Bill Bishop, a business consultant and media industry analyst in Beijing, wrote on his blog, DigiCha, that the new limits could drive television viewers to look for entertainment on the Internet. On the other hand, he added, officials might be preparing restrictions for online video content. "The trend in China appears to be towards more, not less, regulation," he wrote. "Investors may want to consider factoring in greater regulatory risk." To liberalisation of popular culture, China says 'enough'