The air quality in many cities across Uttar Pradesh deteriorated a day after Indians celebrated Diwali with firecrackers despite the ban.

Firecrackers were burst in several Uttar Pradesh districts such as Meerut, Ghaziabad, Noida, Hapur and Bulandshahr, leading to the dip in the Air Quality Index (AQI).

In Meerut, the AQI dipped to the ‘severe’ category (over 400) late on Thursday, while on Friday morning, the air quality touched the ‘very poor’ category (at 390).

Meanwhile, the AQI of Ghaziabad reached 405 on Thursday night and improved to 394 early Friday. At one point in the night, the AQI in Ghaziabad was recorded at 450.

The AQI in Lucknow was recorded at 263 on Friday.

The Air Quality Index is a number through which the quality of the air is ascertained. Along with this, the level of pollution that may occur in the future is also ascertained. The Air Quality Index of every country varies depending on the pollution factors found there.

AQI is divided into six categories. An AQI between 0 and 50 is ‘good’, 51 and 100 ‘satisfactory’, 101 and 200 ‘moderate’, 201 and 300 ‘poor’, 301 and 400 ‘very poor’ and 401 to Between 500 is considered in the ‘severe’ category.