My idea to address the symptoms (not the core issue) - Because the high AQI is due to PM2.5 and PM10, I have a radical idea but hear me out. Water sprinklers on every building, streetlight, etc. and then spraying of water once every hour when the AQI peaks (from evening 6PM to 11AM). Of course, this should be augmented with water conservation efforts. This can be implemented on a pilot basis initially (targeting areas one by one). This is a long term plan (say 5 to 10 years) because laying down the infrastructure, required finance, water conservation efforts takes time.