Barcelona is backing a multi-nation effort to surpass IMO 2020 regulations for ships sailing the Mediterranean Sea.
The city council is "subscribing in favour" of forming an environmental control area (ECA) over the entire water body that would limit sulphur content of ship exhaust to 0.1%.
The International Maritime Organization is requiring the limit to fall to 0.5% from 3.5% by 1 January 2020.
Several environmental groups, including Alianza Mar Blava and Transport & Environment, congratulate Spain's capital for its support under Pedro Sanchez, Spain's new Socialist prime minster since June.
The government opposed the plan earlier in the year under Republican prime minister Mariano Rajoy.
"The establishment of a regulatory framework for ECAs in the North Sea, the Baltic Sea and the English Channel has led to immediate improvements in air quality of up to 50% since 2015 and associated socio-economic benefits valued in billions of euros," the Nature and Biodeversity Conservation Union (NABU) said.
Still, the European Commission estimates that 50,000 Europeans die early every year from ship-created air pollution from nitrogen oxides, sulfur oxides, tropospheric ozone and particulate matter.
The CleanCruiseNetwork alliance of Mediterranean NGOs launched a campaign with the Rome Declaration to gain support for the Mediterannean ECA, which will require docked ships to take power from the electric grid only.
