Both the cities have been reporting worse levels of air quality with the onset of winter.
As of Tuesday morning, Mumbai's air quality index (AQI) is in the 'poor' category while Delhi's AQI sits at 'moderate.'
As per the System of Air Quality and Weather Forecasting And Research (SAFAR), Delhi has an overall AQI of 152 and Mumbai of 225.
Stations around Delhi's Dhirpur, Delhi University and Noida, however, still reported AQI within the 'poor' category.