Ancient Rome was the backdrop for the latest protest staged by the international environmental group Greenpeace against polluting cars. Activists say a new European standard aimed at reducing automobile carbon dioxide emissions must not be lessened. Sabina Castelfranco reports from Rome.

Greenpeace activists staged a bit of theater to make their point against polluting cars.  Some dressed as barbarians drove three German cars: a Mercedes, a BMW and a VolksWagen into Circus Maximus Saturday morning.  Other activists dressed as ancient Romans blocked the cars in a symbolic show of protest.

One of the costumed activists explained the significance of colorful protest.

"I am a barbarian, just like car-manufacturers are," the activist says, "because they do not reduce their carbon dioxide emissions in such a devastating climate."

Greenpeace blames the Italian government for backing German carmakers in efforts to diminish new planned legislation on carbon dioxide emissions for cars.

Campaign Director Giuseppe Onufrio explains. "German car producers are heavily lobbying the European Commission to lower the existing proposal on the regulation for the CO2, carbon dioxide emissions for cars," he says.

The European Union has proposed reducing emissions by 130 grams per kilometer by the year 2012, and reducing another 95 grams by 2020. Greenpeace says governments including, Germany, Italy, France and Britain have been applying pressure to lessen these objectives.

Andrea Lepore is one of the Greenpeace campaigners. "They are trying to weaken the first European legislation to reduce emissions from passenger cars," he says.

Activists unrolled a banner in Latin that read: "Go back CO2.  Polluters will not prevail."  They accused Italian Prime Minister Silvio Berlusconi, whom they described as the new Roman Emperor Nero, of helping to destroy a new proposed E.U. energy and climate package.