Water froze on the walls of the environmental protection bureau's office in Shizuishan, Ningxia Hui autonomous region.
An attempt to use a spray of mist to trick an air pollution monitoring station failed when the water froze in the winter air－providing proof that someone was trying to tamper with the results.
The mist cannon had been used from Dec. 2 to 5 to clear the air around a national air quality environment monitoring station, which coincidentally sat on top of the environmental protection bureau's building in Shizuishan, Ningxia Hui autonomous region. However, the water began running down the side of the building and turned to ice, the autonomous region's environmental protection department said.
Pictures of the ice-laden building went viral online on Tuesday, with many comments calling for strict controls on governments and related authorities.
Two leaders in charge of the mist cannon have been punished for interfering with the monitoring facility.
The regional environmental authority urged a thorough survey of monitoring stations and stricter punishment to avoid manipulation of monitoring data.
This was the third similar case exposed since Jan. 14, when the Ministry of Environmental Protection highlighted two other cases－in Xinyu, Jiangxi province and Xinyang, Henan province－of mist cannons being used to improve monitoring data over concerns that poor air quality would negatively influence performance assessments, the ministry said.
In the two earlier cases, the directors responsible also received administrative punishments.
"Interfering with a monitoring facility can lead to severe punishment, even criminal penalties, which should play a better role in deterring the violators, including government departments," Wang Canfa, a professor of environment law at China University of Political Science and Law, said on Tuesday.
Falsifying monitoring data has been added to the country's list of environmental crimes, according to a new judicial interpretation of the Chinese Criminal Law, effective Jan. 1, 2017.
Wang added that the frequency of such cases shows that the current punishment is not an effective deterrent, and so it is necessary to make specific provisions about the crimes, which could prevent future violations.