China tests air from North Korea for Covid

Beijing installs machines to monitor winds on the border as cases continue to grow in city of Dandong

CHINA is testing the air blowing from North Korea for traces of Covid-19 and encouraging people living along the border to shut their windows on days with a southerly wind.

A video obtained by CNN showed Chinese officials installing air monitoring machines next to the Yalu River that separates the two countries in the northeastern border city of Dandong, through which about 70 per cent of North Korea’s trade passed before the pandemic.

The machines are believed to be checking for Covid-19 droplets blowing in the breeze from North Korea, which has recently experienced its biggest outbreak of the virus.

Earlier in June, Chinese residents living near the river, which measures less a kilometre wide in some spots, were ordered in a government notice to close their windows and refrain from walking by the river. They were also asked to go for more frequent testing.

Authorities have also cracked down on smuggling across the river, offering cash incentives for information on those involved.

The move appears to have been prompted by unexplained chains of transmission in the city of 2.19 million. Dandong, which has long been a trading hub with North Korea, has seen one of the most heavy-handed lockdowns of China’s “zero-covid” strategy.

There is no clear scientific evidence to support the theory that infections are possible through airborne transmission over long distances, and the Chinese authorities have not commented further on its advice.

Ben Cowling, chairman of epidemiology at the University of Hong Kong’s school of public health, told Bloomberg it was unlikely that the infection could spread in this way, explaining that viruses don’t survive particularly well under sunlight and in the open air.

Meanwhile, Peter Collignon, professor of infectious diseases at the Australian National University, said it was more likely that the movement of people, either across the border or within the city, was the cause of the spread. Essential workers could have also fuelled it.

China’s zero-covid strategy has been repeatedly tested by infections leaking across its long-land borders, including its frontiers with Myanmar and Russia.

Officials have been closely watching developments in North Korea after it was hit in April by its first major Covid-outbreak, and the government in Pyongyang declared the “gravest national emergency”.

Little information has emerged from Kim Jong-un’s hermit state but suspected cases topped four million by late April. Pyongyang has since declared victory, lifting its own lockdown and claiming Covid is under control while China has continued its policy of isolating communities and imposing quarantine camps on citizens who test positive.

Earlier this month, Hao Jianjun, the mayor of Dandong, apologised as widespread dissatisfaction grew over the government’s draconian Covid response, admitting the authorities’ work and basic services had been “unsatisfactory”.

The apology was highly unusual for a ranking Communist Party official, particularly as the zero-covid policy has been constantly promoted by President Xi Jinping and top party officials.