Illustration: Rustam VaniaThe International Agency for Research on Cancer (IARC), a part of the World Health Organization, gives its scientific verdict that diesel engine exhaust can cause lung cancer in humans. In its report released on June 12, IARC has reclassified diesel exhaust from its group 2A list of probable carcinogens to its group 1 list of substances that have definite links to cancer. IARC-WHO has now changed the status of diesel exhaust from “probable carcinogen” to “carcinogen”.