High rise buildings are seen through dense smog in Mumbai, India, 16 November, 2023. Mumbai becomes the second most polluted city in the world. The data from 109 places was tracked by a Swiss technology company IQAir, measuring the air quality in real-time. Beijing took the top spot in IQAir’s list. Delhi came out to be the sixth most polluted city. The concentration of fine particulate matter (PM2.5) in Mumbai was 14.7 times according to the World Health Organization (WHO) guideline of five micrograms per cubic metre according to an Indian media report.