A South Korean professor's research is offering a rare glimpse into life in North Korea by analyzing trash that washes up on his country's beaches near the northern border.

"When the wind blew and the waves ran high, something always washed ashore and I was so happy because I could find something new," Kang Dong Wan, a professor at South Korea's Dong-A University, told The Associated Press.

Prior to the pandemic, Kang regularly visited towns in northern China to meet with North Koreans staying there and photograph the North Korean villages across the border. But because of China's COVID-19 restrictions limiting foreign travellers, he can't go there anymore.

Since September 2020, Kang has visited five South Korean border islands off the country’s west coast and collected about 2,000 pieces of North Korean trash including snack bags, juice pouches, candy wrappers and drink bottles.

Analyzing these pieces of litter can open up fascinating insights into the secretive country. For instance, a candy wrapper that lists tree leaves as a replacement for sugar may indicate a scarcity of sugar in the country.

Kang also says the discovery of more than 30 kinds of artificial flavour enhancer packets could mean that North Korean households cannot afford more expensive natural ingredients like meat and fish to cook Korean soups and stews. Many South Koreans have stopped using them at home over health concerns.

The variety, amount and increasing sophistication of the trash, Kang believes, also confirm North Korean state media reports that leader Kim Jong Un is pushing for the production of various kinds of consumer goods and a bigger industrial design sector to meet the demands of his people and improve their livelihoods.

"At first, I was discouraged when people would say, 'Why is a professor collecting garbage?' But now I'm heartened by what I found," Kang said.

"This can be very important material because we can learn what products are manufactured in North Korea and what goods people use there."

With files from The Associated Press