Advocates for a low-carbon economy cried foul over a European decision to ease restrictions on oil sands produced from Canadian fields.

The European Commission ruled Tuesday to pull back on some of the low-carbon policies governing oil sands. The Canadian government has lobbied for the measure as it tries to diversify an export economy based almost exclusively on the United States.

Caroline Lucas, a member of the British Parliament for the Green Party, told the Independent newspaper the European decision was shameful.

"It completely defies reason, enormous public opposition and paves the way for big business to profit from gross exploitation of the earth's resources," she said in comments published Tuesday. "Tar sand oil is one of the dirtiest, most polluting fuels."

Oil produced from Canada is said to be more carbon-intensive than other grades. The European Union aims to cut its emissions from fuel by 6 percent of their 2010 levels by 2020, but last year the Canadian government said oil sands in some cases produces the same or fewer emissions than conventional crude oil from countries like Nigeria or Venezuela.

Agreements signed in July under the so-called Canada's Oil Sands Innovation Alliance call for the development of new technologies meant to reduce greenhouse gas emissions and water usage from the production of oil sands in Alberta.

Greenpeace, however, characterized Canadian crude oil as a "climate wrecking" energy source.