Thousands of Mongolians stood in frigid weather Saturday for the second time this winter to protest the government response to smog that routinely blankets their capital.

An estimated 7,000 people, many of them wearing air masks and gas masks underneath thick winter hats, braved subzero temperatures. Standing in the city’s central Sukhbataar Square, they held black balloons and protest signs. One banner read: “Wake up and smell the smog.”

Ulaanbaatar is one of the world’s coldest capitals, and more than half of the city’s 1.3 million residents rely on burning raw coal, plastic, rubber tires and other materials to stay warm and cook meals in their homes. In impoverished neighborhoods that ring the city, known as ger districts, many herders and others live in traditional round tents without heating, leaving them to burn polluting fuels.

UNICEF, the United Nations’ children’s agency, said last year that Ulaanbataar was one of the 10 most polluted cities in the world. It found that the lungs of children living in the districts with the highest pollution did not function as well as those of children living in rural areas, putting them at risk of chronic respiratory diseases as they age.

Pollution readings in one ger district Friday were occasionally nearly 30 times above the levels considered safe by the World Health Organization. Icy winds that whipped through the square during Saturday’s protest cleared some of the previous day’s pollution.

Sanchir Jargalsaikhan, a political scientist in Ulaanbaatar, said climate change has intensified summer droughts and winter cold, making it harder to maintain livestock and forcing more herders into overcrowded ger districts.

“The policies our government is pursuing are pretty piecemeal, I would say,” Jargalsaikhan said. “They’re not part of a development project or a comprehensive program.”

Mongolia’s environment and tourism minister, Oyunkhorol Dulamsuren, said in December that the government spent more than $37 million and international donors $47 million between 2011 and 2015 on measures to cut down air pollution.

But many protesters Saturday said that they didn’t have the means to do more on their own. Dorjin Dolgor, a retiree, said she lives on an annual pension of about $112. She burns coal in the stove of her house to stay warm.

She called herself a “smogmaker” by necessity.

“To get heaters for my three-room house would cost me one year of my pension, and maybe not even be enough,” she said. “That is the real price. And on top of that, we don’t know how my electrical bill would be afterward.”

— Associated Press