Jan. 11 (UPI) -- A winter storm with high winds has disrupted transportation in Kazakhstan and led to "black snow" falling on the industrial city of Temirtau.
The snow mixed with mysterious, dark dust that has accumulated in the city, which is vital to Kazakhstan's iron industry and houses the country's biggest steel production plant -- Karaganda Metallurgical Combine -- owned by ArcelorMittal Temirtau, a subsidiary of the global industrial giant ArcelorMittal.
"We can't live like this. We're suffocating here," one user wrote on social media.
Angry residents started a petition addressed to Aliya Nazarbayeva, the youngest daughter of President Nursultan Nazarbayev and the head of the Association of Ecological Organisations of Kazakhstan.
"The snow acts as a litmus test, revealing the frightening scale of these harmful emissions," the letter said. "All that dust from the plant ends up in our lungs, and in the lungs of our kids."
ArcelorMittal Temirtau said pollution caused by its plants may have played a major role in the black snow.
"Emissions do not dissipate and this most likely caused the change of the snow's color," the company said.
In December, the national meteorological agency recorded levels of hydrogen sulphide in Temirtau that were 11 times greater than the government-mandated limit.
Independent ecologists and government experts are working to identify the causes of the black snow.
The latest snowstorm in the central Asia country cut highway to and from the capital, Astana, and left other regions isolated.
On Thursday, Astana's Mayor Aset Isekeshev declared a state of emergency after strong winds and snow drifts forced the closure of Nursultan Nazarbaev International Airport.
Interior Minister Qalmukhanbet Qasymov said all roads in the regions of Aqmola, Qaraghandy, Pavlodar and Qyzyl-Orda were closed.