Pollution levels in Delhi are lower compared to the air quality recorded during Diwali in 2016, IANS reported quoting the Central Pollution Control Board. The board’s air quality index ranked Delhi’s level as “very poor” at a 322 value. In 2016, the city’s air quality levels were ranked at a “severe” level with an index value recording of 431, the news agency reported.

On October 9, the Supreme Court had said it wanted to assess the difference in air quality in the highly polluted region after the firecracker ban.

The board’s data attributed Thursday’s air quality levels to particulate matter that are tiny particles in the atmosphere that can easily enter a peoples’ lungs.

The CPCB data, recorded at 4pm, described the air quality levels in Rajasthan’s Bhiwadi as “severe” but later updated it to a “very poor” status. In Chennai, the Tamil Nadu Pollution Control Board found particulate matter levels had risen significantly this Diwali when compared to the festival time in 2016. The Central Pollution Control Board data said Chennai’s air quality levels were “poor”.

The air quality levels in Kolkata and Mumbai were pegged “moderate”.

According to the grading system, “severe” is the lowest rank and “good” an indicator of minimal impact.

In 2016, the alarming smog after Diwali celebrations in Delhi-NCR had forced schools to remain closed for three days, and the National Green Tribunal had declared an environmental emergency in Delhi, Haryana, Punjab, Rajasthan and Uttar Pradesh.

The Supreme Court-appointed body, the Environment Pollution Prevention and Control Authority, on Tuesday banned diesel generators in Delhi after the air quality entered the “Red Zone”. The Badarpur power plant was also shut down, and hundreds of brick kilns were also ordered to stop production.