Mumbai's overall air quality remained considerably better than Delhi's, but several parts of the city witnessed a sharp rise in particulate pollution. A thick blanket of smog enveloped Delhi on Diwali night as firecracker emissions pushed air quality into the 'severe' category at 20 monitoring stations, with. Diwali smog pushes Delhi near severe AQI, with spikes across major Indian cities and Stage III GRAP restrictions in effect.