By Ha Er-rui | 2026-07-24

Thai demonstrators are demanding an end to Chinese-financed pollution of their rivers.

Protesters marched through Bangkok carrying placards reading, "This is Thailand, not Tiananmen," and "Stop violence against environmental defenders." Other signs demanded, "Pollution has no borders. Responsibility shouldn't either," and "Clean energy should not cause dirty rivers."

Angry Thai residents demonstrated outside the Chinese consulate in Chiang Mai on July 6 and the Chinese embassy in Bangkok two days later. They were protesting Chinese-backed gold and rare earth mines in Burma, which they say have severely polluted downstream rivers.

Arsenic and lead pollution

The protesters were reacting to excessive levels of arsenic and lead in northern Thai rivers. Authorities have been monitoring the rivers for heavy metals since alarming events began unfolding in late 2024.

The once-clear Kok river had turned muddy, the Bangkok Post reported in May 2025. Children who played in the river developed rashes. Farmers found their crops wilting.

Authorities in early 2025 found arsenic and lead levels above safe limits in Mae Ai district, Chiang Mai province, the Bangkok Post reported at the time.

A year later, Thai authorities tested various rivers in Chiang Mai and Chiang Rai provinces April 27–May 1 and discovered still-abnormal arsenic levels in the Kok and Sai rivers. They also found an unsafe level of manganese in the Sai river, according to Thailand's The Nation news site.

1 protest turns violent

While the Bangkok gathering remained peaceful, the earlier protest in Chiang Mai turned violent, leaving two demonstrators injured.

Demonstrators in Bangkok wore masks depicting Chinese President Xi Jinping, while protesters in Chiang Mai symbolically prepared larb pla -- a spicy Thai dish made with raw fish caught from the contaminated Kok river.

Reading a statement outside the Chinese embassy in Bangkok, Lertsak Kamkongsak, chairman of the NGO Coordinating Committee on Development (NGO-COD), urged Beijing to prioritize resolving trans-boundary pollution.

Mining during a civil war

The statement cited reports of heavy metals detected in northern Thailand's waterways and demanded an investigation of Chinese-backed mines in Shan state, Burma. Cross-border investments must come with environmental safeguards and corporate accountability for affected downstream communities, Lertsak emphasized.

Chinese-backed mining has expanded rapidly into Burmese territory beyond the junta's control during the country's civil war, say protest leaders.

That growth of mining on territory lacking effective oversight leaves downstream communities with little chance of holding polluters accountable, they say.

Demanding Chinese accountability

China supports closer coordination between Thailand and Burma, a spokesperson for the Chinese embassy in Bangkok said. The embassy urged the countries to jointly investigate the problem as soon as possible.

Protesters, though, demanded Beijing match its professed commitment to having Chinese companies abroad comply with host-country laws as well as with "international environmental and human rights standards," according to NGO-COD's statement on Facebook.

China must not build its prosperity "on the death of rivers and communities beyond its borders," the statement added. "If profits can cross borders, responsibility must cross them as well."