The AQI in Mumbai is in the news due to severe levels of pollution caused by firecrackers during Diwali. According to the NDTV Profit report, the city and Thane are experiencing high levels of air pollution. The report does not provide specific details on the exact AQI levels or the duration of the pollution. However, it mentions that the pollution is severe enough to be classified as a major issue. The report attributes the pollution to the use of firecrackers during Diwali celebrations. The exact impact of the pollution on the residents of Mumbai and Thane is not specified in the report. The report only mentions that the pollution is a significant concern. The report does not provide information on any measures being taken to mitigate the pollution.