Air pollution is as injurious to health as smoking cigarettes, according to Dr Arvind Kumar, Chairman, Institute of Chest Surgery, Chest Onco Surgery and Lung Transplantation at Medanta. In the past three decades, Dr Kumar has noticed some very fundamental and frightening changes in the colour of the lungs of people as well as in the spectrum of people coming to the outpatient department (OPD). In an exclusive interview with NDTV-Dettol Banega Swasth India, Dr Kumar shared his experience and painted a before and after picture of the kind of lungs he used to operate on vs now.