A researcher, presenting results of his three-month-long study, claimed that the air in Kathmandu contains harmful heavy metals nine times more than in natural air. Dr Mukesh Kshetry, a teacher at the Amrit Science College, presented this grim fact at an interaction organised by the Martin Chautari today. The concentration of heavy metals is higher in the areas where more vehicular movements occur, he added. "Every kilogram of air outside the Kathmandu valley, considered natural air, contained 5.7 milligram of heavy metal against 30.4 milligrams in the air within the valley," he said.

The study was based on close observation of amount of heavy metals deposited on lichen and moss samples found in and outside the valley, he clarified. Some 90 elements are reported to have existed in the air across the world of which 53 heavy metals and some of the heavy metals are hazardous. "Lead, zinc, mercury, copper, cadmium, uranium are very harmfu." Air in busy areas like Kalanki, Thapathali, Lagankhel, Ratnapark contained more amount of heavy metal. Most of these places are bus or tempo stations.