Cheyenne, Wyo. A rule that phases out snowmobiling in Yellowstone and Grand Teton national parks took effect April 23, but officials said they will not start enforcing it until the end of next year.

The Clinton administration had approved the ban, saying it would
reduce pollution and noise. It was to take effect two months ago,
but was delayed because the Bush administration wanted to review
it.

The ban may be short-lived: Justice Department officials and
snowmobile manufacturers are in talks to settle a lawsuit
challenging it. About 62,000 snowmobilers visit Yellowstone each
winter.