EU member states on Tuesday agreed new rules to limit pollution from hundreds of thousands of medium-sized power plants that had previously escaped regulation.
The compromise deal to curb sulfur dioxide, nitrogen oxide and dust from combustion plants with a thermal input rated between one and 50 megawatts now requires just a formal sign-off from the European Parliament, expected later this year.
Environmental campaigners said the draft rules had been weakened significantly during negotiations so existing plants would get more time to comply than new plants.
But they said the rules were a step in the right direction as, until now, only large plants, such as coal- or gas-fired power stations, oil refineries and steel producers, had been subject to limits.
"This is a key piece that was missing and that will help to significantly reduce the potential risks to human health and the environment," Kaspars Gerhards, environment minister for Latvia, holder of the EU presidency, said in a statement.
According to EU figures, there are 143,000 medium-sized combustion plants, including coal- and biomass-fired facilities and district heating, in the European Union.
Louise Duprez, a senior policy officer at the European Environmental Bureau, called on member states to introduce more stringent limits than those required by the new law.
"The weak result is unlikely to deliver significant improvements to air quality," she said.