Chongqing's Wushan clears 20,000 tons of river debris in the Yangtze annually

"Even though it's already May, the weather conditions these days have been favorable, resulting in a relatively clean river. Thereby, we only deploy three mechanized debris-clearing boats today," Yu added.

A routine water quality assessment conducted on Wednesday showed that water quality had even reached Class I — the best level on China's five-tier grading scale — at that time, said Wei Wei, an official from the county's ecology and environment bureau.