Come winter and the number of people suffering from respiratory ailments increases. Today, most of the big cities in India share the same sad picture and Ahmedabad is no different.  Professor Ashutosh Kumar, Division of Biological and Life Sciences, has been working on particulate matter and demonstrated that the release of particulate pollutants into the air through the burning of coal, crude oil, diesel, coal tar, etc. raises concerns of potential health hazards to the exposed human population. Polycyclic aromatic hydrocarbons (PAHs) are major toxic constituents of particulate matter, which upon ingestion get metabolized to even more toxic metabolites such as quinones. The PAHs levels were assessed in both respirable particulate matter (RSPM, <10 micrometres) and suspended particulate matter (SPM, >10 micrometres size) of urban ambient air (UAA) and that of major contributors viz. diesel exhaust particles (DEPs) and coal tar combustions emissions (CTCE). This has also been observed that the particulate matters associated PAHs for UAA have potential to induce mutation (as confirmed by Ames Test) and DNA damage (as confirmed by comet assay) in human lung alveolar (A549) and bronchiolar (BEAS-2B) cells.