more than a quarter of the air pollution in Tehran comes from motorcycles. Most attention is focused on cars, but the official said that motorcycles made in Iran adhere to the Euro 2 pollution standard when the EU has already moved up to the much stricter Euro 5 standard. He said more attention should be focused on motorcycles, which he said cause 25-30 percent of Tehran’s air pollution, 40-45 percent of traffic accidents and half of all the sound pollution.