More than one million websites closed down in China in 2010 after the government tightened controls on the internet, according to a study by a leading state-run research institute.
The Chinese Academy of Social Sciences said there were 41% fewer websites at the end of 2010 than a year earlier, but claimed there is no link with a government crackdown in 2009.
The researchers said although thousands of sites were shut down, the actions of the government were mainly aimed at putting a stop to online pornography, but critics have said other sites also closed.
The researchers also insisted there is a "high level" of freedom of online speech, with few cases in recent years of sites being closed purely to control speech, according to the BBC.
"Although the internet is posing some problems for new media, our regulation is becoming stronger, we have taken a very big step in this area," researcher Liu Ruisheng was quoted as saying on the organisation's website.
The researchers said that despite the declining number of sites, the number of web pages rose to 60 billion during 2010, representing a 79% increase on the previous year, which means content is getting stronger while supervision is becoming stricter and more regulated.
But civil rights campaigners said a number of legitimate websites are routinely blocked, such as the BBC's Chinese language service, Gmail and social media sites such as Facebook, YouTube and Twitter.
Earlier this year, Chinese web police censored internet calls for Arab-style uprisings in China, and earlier this month the government censored all postings on China's Twitter-like microblog Weibo that referred to reports that former president Jiang Zemin is seriously ill.