Authorities in Vietnam have arrested more than 70 people, including government officials, accused of falsifying data from air and waste water monitors at power plants and other major emitters, state media said Sunday.

The state-run People’s Police newspaper said police had identified “nearly 160 environmental monitoring stations that had been tampered with, altered and had their data falsified” – accounting for more than half of the total number of stations nationwide.

Police arrested 74 people, including officials at state environmental agencies and others at dozens of businesses that discharge waste water and install monitoring equipment, on charges related to environmental monitoring violations, the newspaper said.

“Even though the monitoring equipment is sealed and has its own surveillance camera system, it was still being remotely adjusted via software,” the state-run outlet said.

“The perpetrators interfered to reduce the output indicators thereby ensuring that the data sent to the management agency always remained within permissible levels.”

Authorities said data sent to local environment departments from large-scale emitters of air pollution and waste water, including the Quang Ninh Thermal Power Plant, Hai Phong Thermal Power Plant and Thai Binh 2 Thermal Power Plant, as well as aluminium and steel companies, were “being manipulated and altered in a sophisticated manner”.