A new report indicates that the ozone hole in the Earth’s atmosphere has shrunk to its smallest size since 1988, although that’s not necessarily an indicator that our planet is on the mend. The hole reached the maximum size on Sept. 11, and NASA measured it at 7.6 million square miles wide, which is a solid 1.3 million square miles less than 2016, and a staggering 3.3 million square miles smaller than 2015.

NASA says that stormy conditions have warmed the air and kept ozone-eating chemicals out of the upper atmosphere, and that’s a driving cause for the change. It’s a natural shift that doesn’t necessarily mean our environmental situation is dramatically improving, but it’s certainly not a bad sign.

In fact, scientists think that our efforts to keep ozone-eating chemicals out of the air are at least helping a little bit. The ozone hole hit its peak back in 2000, when it was 11.5 million square miles.

“The Antarctic ozone hole was exceptionally weak this year,” said Paul A. Newman, chief scientist for Earth Sciences at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “This is what we would expect to see given the weather conditions in the Antarctic stratosphere.”