In a unanimous decision, St. Lawrence Cement Inc. will pay damages to 2,000 people of Quebec City who complained the plant was interfering with their enjoyment. The class action was launched in 1994; the plant was closed in 1997.

"This is a massive victory," said Will Amos, a lawyer for the environmental group Ecojustice. "It is going to make it much easier for citizens to make environmental-nuisance complaints, they are not going to have to prove fault or wrongdoing. They have only to prove that an abnormal annoyance occurred. That is absolutely critical."

The decision means polluters can be successfully sued for emitting annoying odours, dust or noise even when in compliance with government regulations. The court said polluters must pay "based on the annoyances suffered by the victim being excessive, rather than on the conduct of the person who allegedly caused them."