China’s top environmental watchdog has launched a pilot field survey of wastewater outlets that discharge into the Yangtze River, as preparations for a campaign to map all such outlets along the country’s longest waterway gain momentum.

More than 130 environmental law enforcement officers and experts from seven provincial regions and institutes affiliated with the Ministry of Ecology and Environment, divided into 40 teams, began combing a 98-kilometer section of the Yangtze in Taizhou, Jiangsu province, on March 20 after undergoing a morning training session.

Li Tianwei, a senior official with the ministry’s law enforcement bureau, said during the training that the survey will not overlook any outlets.

“As long as it’s an outlet with access to the river, it should be recorded,” he said.

China has increasingly emphasized protection of the Yangtze since early 2016, when President Xi Jinping urged provincial regions along the river to concentrate on ecological restoration and protection, and to avoid large-scale development.

With authorities lacking experience with wastewater outlets along the river, the pilot program will help set technical norms and procedures that can be applied in a comprehensive survey of the 11 provincial-level regions along the Yangtze River Economic Belt, Li said.

He added that the program will help train people for follow-up surveys along the length of the Yangtze, which are expected to get underway in September.

“Those offering to participate this time are potential team leaders in the comprehensive survey,” he said.

He said the ministry will take a series of steps to ensure that all wastewater outlets are recorded in the comprehensive survey. Before the field survey, experts will use remote satellite sensing and unmanned aerial vehicles to identify suspected wastewater outlets.

The ministry will also carry out enhanced surveys in areas where work is challenging because of complicated local conditions, he said, without elaborating.

Guo Qingwei, an expert at the ministry’s South China Institute of Environmental Sciences, reminded his colleagues during training that they must pay particular attention to the blind spots of satellites and drones — under bridges, for example.

Chongqing’s Yubei district was chosen as another pilot area for the outlet survey during a ministry conference in February. The program there will kick off soon, the ministry said.

After the comprehensive river outlet survey, the ministry will monitor the outlets and then trace any pollution to its source. It will also tailor its pollution control steps to each circumstance.