Often the best environmental news is news about what won’t happen. Recently, good news arrived for Maine when a company trying to build an enormous cement plant along the Hudson River, near Albany, N.Y., ended its pursuit after six years of fighting and a lengthy community debate.

The plant planned by St. Lawrence Cement failed to get the approval of the New York Department of State, which had concluded the plant did not meet the state’s coastal zone policies. St. Lawrence decided not to appeal that decision. The plant would have sat on a 300-foot hill and had a smokestack 400 feet tall.

Among the pollutants that would have been emitted were nitrogen oxides, which, along with volatile organic compounds in the presence of sunlight create ground-level ozone ? part of smog ? that irritates the eyes, nose and throat, causing inflammation of bronchial tubes and tissues in the lungs. Asthma sufferers feel it worst, but anyone on a summer day can be affected. According to the environmental group Scenic Hudson, the total nitrogen oxides production from the proposed plant would have been roughly equivalent to 200,000 cars.

This mattered to Maine because of the height of the smokestack. An expert in support of the plant commented a couple of years ago, “The higher stack will disperse the effluents over a wider area. On most days, within six hours, the air mass has gone to Maine.”

For well over a decade, Maine has participated in regional air-pollution strategies under the sensible reasoning that the pollutants don’t stop at state borders. It can be grateful to energetic groups such as Scenic Hudson (whose president is former Maine commissioner of environmental protection, Ned Sullivan) for working with a larger, multi-state coalition, building strong arguments and rallying opponents against the plant, which would have presented an eye-sore locally and sore eyes regionally. Besides air less polluted, environmentalists have the good news of a win during a time of few wins.

Some of the lengthy dispute might have been avoided had the Environmental Protection Agency made final its air-quality rules for national parks and wilderness areas. The rules affect cement plants as well as power plants, industrial boilers, refineries and and pulp and paper mills and many other sources of pollution but have been delayed over the years and just last month, when they were again due, were delayed again until June.