European Union nations could save 50 billion euros (£43 billion) a year by fully carrying out existing environmental laws in areas such as air pollution and waste, the European Commission said on Monday.
Twenty-three of the 28 member states were breaching air pollution quality standards, according to the Commission's Environmental Implementation Review, which it said was a new way to help track and compare environmental performance.
Better health would be the main economic benefit of applying the rules since 520,000 premature deaths in the bloc were blamed on air pollution in 2013, it said.
"Patchy and uneven implementation of environmental rules helps no one," Environment Commissioner Karmenu Vella said in a statement. "Improving how environmental laws are applied benefits citizens, public administrations and the economy."
Full implementation of EU environmental laws "could save the EU economy 50 billion euros every year in health costs and direct costs to the environment," the Commission said.
Among measures to reduce pollution, it urged a phase out of environmentally damaging subsidies, such as for some fuels and tax advantages for company cars that are also used privately.
Apart from air pollution, the Commission said there were big gaps in waste management, nature and biodiversity, noise and water quality and management.
Germany and Slovenia were best in the EU, for instance, in recycling about 60 percent of their municipal waste in 2014 while Slovakia and Malta were bottom with rates of just 12 percent.
The study said that full compliance with waste policies by 2020 would create 400,000 jobs.
And it called for better preservation of nature. It said the EU as a whole was not on track to meet goals for halting the loss of diversity of animal and plant life by 2020.
(Writing by Alister Doyle in Oslo)