"Officials Link Pig Farm Wastewater to Mass Fish Deaths in Vientiane Province", 18 May 2026

Authorities in Vientiane Province have identified untreated wastewater from a pig farm as the primary cause behind the mass fish deaths reported along the Nam Cheng river in Viengkham and Phonhong districts earlier this month.

The incident occurred after heavy storms and rainfall …, when residents observed and reported the water turning dark black and muddy, accompanied by a strong foul smell, while large numbers of fish were found dead as well.

According to findings released by the Department of Natural Resources and Environmental Inspection ..., officials conducted field inspections together with relevant departments to collect water samples from three locations.

Laboratory analysis found that water quality levels had exceeded national environmental standards. As a result, pH levels reached between 9 to 11, indicating highly alkaline and toxic conditions unsuitable for fish.

Dissolved oxygen levels also dropped below standards for sustaining fish and other aquatic species.

Officials pointed out the polluted water contained large amounts of waste, which consumed oxygen in the stream as it broke down. This caused the water to smell bad and left fish and other aquatic animals struggling to live.

Following on-site inspections, officials identified the most likely source of pollution was wastewater discharged from the Zhang Weixing breeding and commercial pig farm project, according to the official Facebook page of the Lao Ministry of Agriculture and Environment…

In response, the Vientiane provincial authorities have temporarily suspended the pig farm’s operations while authorities review its environmental management systems.

Officials also announced additional measures, including expanded water quality monitoring, inspections of businesses operating along the river, environmental risk assessments, and legal investigations into those responsible for the pollution and environmental damage…