Coal-dependent Poland could face a fine after it became only the second European Union country ever to be formally told it was breaching air pollution limits.
The EU’s top court ruled the country had failed to uphold air quality standards.
The European Court of Justice said Poland broke air pollution laws by exceeding annual limits for particulate matter smaller than 10 micrometres (PM10), which can damage health if breathed in.
Campaigners say Poland’s problems stem from the fact it burns too much coal.
A report in 2016 claimed the country’s coal facility at Bełchatów was the EU’s most-polluting plant.
Poland was taken to court by the European Commission as part of a wider EU battle to reduce deaths from airborne pollution, which it estimates causes the premature death of at least 400,000 people every year.
"It's more bad news for Polish people,” said Agnieszka Warso-Buchanan from environmental NGO Client Earth. “Not only do they have to live with losing the case, they also still have to breathe harmful air. The actions of the Polish authorities are far too slow in relation to the threat level.
"For years, the Polish authorities have been aware of the scale of the problem and the actions required for them to reduce air pollution and thus protect people’ health.
“Their actions can be described in three words: ineffective, inadequate and negligent as Air Quality Plans are too vague, quality requirements for solid fuels are still missing and the standards for stoves only apply to new devices.
"The main cause of air pollution in Poland is burning coal. The question is: is coal more important than people’s health? We hope that the government will put the interests of all Poles over the interest of the coal industry.”
She added Poland could face a fine in the future if it continues to breach limits.
The country’s dependence on coal and commitment to renewable energies was explored in a recent Euronews report.
Tomasz Szczerba, mayor of a town called Wojkowice, home to an EU-funded solar farm, told us Poland’s coal industry was deeply-ingrained.
“The coal industry is some kind of tradition,” he said. “This is our history. For example, my father and grandfather were working in the coal industry, a big plant and you know, this is not easy to solve this problem, like this (clicks fingers).”
Bulgaria is the only other country to have received a similar ECJ judgment to that handed down to Poland.
Last month, the European Commission warned nine other member states, including Germany and the United Kingdom, that it could take legal action if they did not present "additional credible, timely and effective measures" to tackle air pollutants.
Targets introduced to reduce the amount of pollutants for 2005 and 2010 are being exceeded in 23 of the EU's 28 members.
Brussels has at least 30 cases open against member states over air pollution but many of them have been dragging on for years.
Poland’s Ministry of Environment said in a statement to Euronews: "Poland is consistently striving to improve air quality. However, due to many years of neglect in this area, these activities require time and cooperation at the level of government administration and local governments, as well as citizens' involvement.
"The Ministry of Environment informs that at the moment Poland is not threatened by any financial sanctions resulting from today’s verdict announced by the CJEU. Poland is not the only country facing difficulties in reaching the acceptable level of PM10. Currently, 20 Member States are affected by this issue."