A toxic air alert in the biggest metro cities in the country, 20 days before the peak pollution season, which is usually closer to Diwali. Delhi's air quality showed a marginal improvement on Monday and was recorded in the "poor" category, while the city registered a maximum temperature of 31.5 degrees Celsius, normal for this time of the year. In Mumbai, an anti-smog gun was seen in action as the air quality in the city this morning was recorded in the 'moderate' category with an air quality index of 127.