Data released by the CPCB shows Kolkata and Agra as the second and third most polluted cities in the country respectively on Diwali night

In what may come as a surprise to many, especially due to the brouhaha over the ban on fire crackers in Delhi, a report by the Central Pollution Control Board (CPCB) claims that Bhiwadi in Rajasthan’s Alwar district and not the national capital recorded the highest air pollution on Diwali night.

However, before votaries of allowing sale and bursting of fire crackers begin slamming their opponents and claiming that the cracker ban and air pollution aren’t interlinked, here’s the catch – Bhiwadi, too falls within the national capital region (NCR) of Delhi, and ideally should have been covered under the prohibitive order that was issued by the Supreme Court. Additionally, various studies in the past have also established how air pollution in not just the NCR cities but even in western states like Punjab, infamous for stubble burning, directly affects the ambient air quality of Delhi.

The CPCB, in its report of the ambient air quality and related pollution levels in different cities of the country on Diwali, rated Bhiwadi as the most polluted city across India while Kolkata took the second spot and Agra finished third. In 2016, Agra was the most polluted city.

Although the increasing air pollution in Bhiwadi has been attributed to industries emitting harmful smoke, the air quality in the town seems to have worsened further on Diwali night due to the blatant violation of the cracker ban, something that was also witnessed in Delhi and other parts of the NCR.

According to the CPCB Air Quality Index (AQI) report, the level of pollution in Bhiwadi was 425 micrograms per cubic metre. Kolkata recorded the air pollution level at 358 micrograms per cubic metre while Agra recorded 332 micrograms per cubic metre.

Concentration of PM 2.5 (particulate matters that are 2.5 or less than 2.5 micrometres in diameter) was the major contributor to the “severe air quality” in Bhiwadi.

The AQI of Delhi was only marginally ‘better’ on Diwali night – recorded at 319 micrograms per cubic metre – which, however has been graded as “very poor”. Mumbai recorded an AQI of 204 micrograms per cubic metre and was categorised in the “poor”.

The AQI grades air on the basis of pollutants such as PM 2.5 and PM 10; dividing the categories of air in the following categories: Good(0-50), Satisfactory (51-100), Moderate(101-200), Poor(201-300), Very Poor (301-400) and Severe (>401).