The Ministry of Ecology and Environment, China's top environmental watchdog, has launched a campaign to comb the banks of the Yangtze River to map all sewage outlets and identify any that are unregistered.

Water quality monitoring will be done at all sewage outlets, and environmental officers will trace any pollution they find to its source. Tailor-made remediation measures will then be undertaken, the ministry said.

It also said the latest technologies, including satellite remote sensing, unmanned aerial and aquatic vehicles and intelligent robots will be brought into the campaign, which will last for two years.

Chongqing municipality's Yubei district and Taizhou, Jiangsu province, have been chosen as pilot areas for the campaign. The ministry hopes initial work in those places will help establish technical norms and work procedures that can then be extended to all 11 provincial-level regions along the Yangtze River Economic Belt beginning in the second half of this year.

The first priority of the campaign is to clarify how many sewage exits there are, where discharges are happening, who is discharging, and what and how much they discharge, said Zhai Qing, vice-minister of ecology and environment, during a video conference on Friday, according to a news release from the ministry.

In the country's latest institutional reshuffle last year, management of sewage exits in rivers was shifted from the Ministry of Water Resources. According to the top water resources authority's survey in 2017, there were 6,092 major sewage outlets along the Yangtze.

Zhai said the outlet survey this time will be "extended and deepened" based on previous work.

"The biggest difference of this campaign from other previous work on sewage outlets is that it will not overlook any exits that discharge into the Yangtze," he said.

The ministry said outlets with direct or indirect pollution discharges will be targeted in the campaign.

Government bodies have increasingly emphasized the protection of the Yangtze since early 2016, when President Xi Jinping urged officials from provincial areas along the river to concentrate on ecological restoration and protection, and avoid large-scale development.

Early this year, the Ministry of Ecology and Environment and the National Development and Reform Commission published a circular on Yangtze restoration and protection, vowing to comprehensively improve water quality by 2020.

The ministry said it will continue its campaigns focusing on solid waste and on water bodies that supply drinking water along the Yangtze.

The Ministry of Water Resources and the National Energy Administration, along with another two government agencies, launched a campaign at the end of last year to eliminate small hydropower stations.