A study of ice cores from the Himalaya reveal a substantial rise in industrial pollution over the past few decades, claim some Chinese researchers. Ice cores from remote mountain areas are believed to contain accurate records of atmospheric concentrations over tens of thousands of years. Scientists from the Lanzhou Institute of Glaciology and Cryopedology, which is under the Chinese Academy of Science, removed six ice cores from a glacier on Mount Xixabangma, which is 7,100 metres above sea level and located in the central part of the Himalaya. The samples indicate that industrial development, especially the increasing number of motor vehicles, has caused a significant increase in the lead content in the glacier, points out Wang Ninglian, associate researcher at the institute. It has also been found that the density of methane in the glacier is much higher than that of ice cores from polar regions. The samples also contain residues of oil fires ignited during the 1990-91 Gulf War ( News From China , Vol 11, No 14).