A U.S. scientist says Mount Everest and its surrounding peaks are increasingly polluted and warmer, and nearby glaciers are melting at an alarming rate that is likely to make it more dangerous for future climbers.

Prof. John All of Western Washington University and his team of scientists spent weeks testing snow on Everest and surrounding peaks, as well as plants on the foothills.

All said Tuesday after returning from the mountains that they found there was lot of pollution buried deep in the snow, and that the snow was surprisingly dark when they processed and filtered it.

The scientists said the samples and data would be processed once they return to United States. They said they would issue then a report on their findings.