Air pollution in Delhi has moved far beyond being an environmental issue. “Air pollution is a slow poison,” says Dr Arvind Kumar, Chairman of the Chest and Lung Transplantation Department at Medanta – The Medicity. Delhi’s polluted air is not a single contaminant—it is a toxic concoction of microscopic particles and obnoxious gases. According to global health agencies, air pollution is now among the leading causes of lung cancer worldwide. “Air pollution causes repeated injury to lung cells,” explains Dr Kumar.