Disgruntled fans shared subtitled screenshots from a Big Bang Theory episode online in which the character of Sheldon Cooper talked about the Chinese Communist Party.

“I like China,” he says in the episode. “See, they know how to keep people in line.”

Many posted swear words and icons of candles to express their indignation over the ban, which was one of the most widely discussed topics on microblogs today. 

There can be no Internet freedom without order, the top Communist Party newspaper said today, explaining why the series had been pulled from streaming websites.

“While ordinary people and governments have enjoyed the conveniences brought by the internet, they have also in turn experienced the internet’s negative effects and hidden security dangers," the People’s Daily, the party’s main mouthpiece, said in a commentary.

It was published under the pen name “Zhong Sheng”, meaning “Voice of China”, often used to give views on foreign policy.

“If you don’t have internet order, how can you have internet freedom? Anyone enjoying and exercising their internet rights and freedoms must not harm the public interest and cannot violate laws and regulations and public ethics,” the paper said.

The removal of the shows coincides with a broad crackdown on online freedom of expression that has intensified since President Xi Jinping came to power last year and drawn criticism from rights advocates at home and abroad.

It comes following a directive from the State Administration of Press, Publication, Radio, Film and Television (Sarft) last month that tightened the process for broadcasting television programmes and short films online.

Programmes and films lacking licences are not permitted to be shown online, according to the Sarft directive. Penalties include a warning and a fine and, in serious cases, a five-year ban on operations and investment in online programming.

But there are no specific regulations governing overseas TV programmes licenced by Chinese websites, said one person who works at an online video site, adding that regulation was expected at some point but with a minor impact on the industry.

China’s online video market was worth 12.8 billion yuan (HK$16 billion) in 2013, according to Chinese data firm iResearch. Market value is expected to almost triple by 2017.

Online video sites are extremely popular and at times act as a lodestone for comment on social issues. Users upload videos documenting corruption, injustice and abuses attributed to government officials and authorities.

Sarft has been in discussions with online video sites about greater control of their content since 2009, according to people familiar with the matter.

China maintains tight control over the media. Censorship is widespread, and internet users cannot access information about many topics without special software to circumvent restrictions.

Authorities last week also stepped up their battle against pornography, revoking some online publication licences of one of China’s largest internet firms, Sina, for allowing “lewd and pornographic” content.

The Communist Party last year renewed a campaign on online interaction, threatening legal action against people whose perceived rumours on microblogs like Weibo, are reposted more than 500 times or seen by more than 5,000 people. The campaign has muted online demands from advocates of transparency, who see it as a tool to punish the party's critics.

Pornography is illegal in China, but critics say the crackdown on material deemed obscene is an extension of government attempts to tighten its grip on the internet.