Dirty work

Over the years, Zhao and his NGO volunteers have encountered multiple threats while conducting surveys. Factory security guards have set their dogs on them to deter them from photographing evidence, while others have tried to grab their phones.

The team members eventually turned to advanced technologies to help them better conduct their surveys, which also reduced the number of threats they encountered.

In 2017, Airman joined a team of experts investigating a sulfur dioxide pollution scandal in Linfen, Shanxi province. They provided an independent report on the hazardous contamination based on aerial footage taken by drones and data processing technologies.

The investigation led to senior officials in Linfen being summoned by the country's top environmental watchdog, and approval of new projects in the city being suspended.

To date, Airman has reported over 1,500 violations to environmental authorities. Many of the cases were also reported to the country's high-profile central environmental inspection team, Zhao said.