Leading Chinese tech firms, including Baidu and Sina, were punished after their cloud storage services were found to contain pornographic materials, according to law enforcement authorities.
The move came after the government recently launched a campaign to crack down on pornographic videos and images distributed via cloud storage services.
The National Office Against Pornographic and Illegal Publications said companies were asked to tighten their supervision of cloud storage services.
The office earlier released details on six cases that involved individuals profiting from the sale of account names and passwords host pornography in the cloud.
In one case, a court in Wuxi, East Jiangsu province, sentenced a man to three years in prison for selling individual accounts that had access to over 10,000 pornographic video clips for 50 yuan ($7.68).
A group of internet video player service providers have been investigated and punished for spreading pornography in a nationwide crackdown, the anti-porn authority said.
In Beijing, local authorities have probed and fined several cloud storage service providers, including Baidu and Sina, for porn distribution via their services.
Tech companies in China could offer users up to 2TB of free permanent storage as competition heats up, but this also leaves room for illegal online activities by some users.
Huawei Technologies Co Ltd's cloud service DBank said earlier this month it would halt cloud storage services to individual users in cooperation with "relevant authorities to clean up pornography and piracy that are spreading on the cloud services."
Last year, more than 1.4 million accounts of 360 Yunpan, a Chinese cloud storage service, were closed after police received information that the platform has been used to store and trade pornographic materials.
