A National Park Service plan to allow 540 snowmobiles a day into Yellowstone National Park has been tossed out by a federal judge. U.S. District Judge Emmet Sullivan ruled Monday that allowing that many ‘mobiles would increase air and noise pollution and be disturbing to wildlife — conclusions drawn, he noted, by NPS’s own data. Increasing the allowed number of snowmobiles “elevates use over conservation of park resources and values,” Sullivan ruled, and NPS “fails to articulate why the plan’s ‘major adverse impacts’ are ‘necessary and appropriate to fulfill the purposes of the park.'” NPS must go back to the drawing board. Conservationists favor kicking snowmobiles out of the park entirely; a new plan is unlikely to go that far, despite NPS research concluding that a snowmobile ban would have “negligible to minor” economic impacts on local communities.