People in Delhi are used to seeing their city top all kinds of charts for the wrong reasons. But when it comes to one of the most dangerous types of air pollutants – PM10 or Particulate Matter 10 – residents of India’s capital city can breathe easy, literally. A clutch of cities from the eastern part of India dominate the list of cities most affected by PM10 pollution.
PM10 measures the amount of inhalable (large) dust particles in the air. It is different from the more well-known PM2.5, often called ‘fine dust’ to distinguish it from PM10, which – for lack of a better term – can be called ‘larger dust’.
Asthma and lung cancer are only two of the deleterious effects of inhaling too much PM10.
Now, let’s come back to the question of which city is the most polluted.
According to Ministry of Environment, Forest and Climate Change records, Jharia in the state of Jharkhand has the distinction of being the worst affected by the PM10 problem in India.
With Particulate Matter emission (PM10) concentration of 281 μg/m3, Jharia is the most polluted city in India, according to data presented in the Rajya Sabha on Thursday.
In fact, all the top five polluted cities belong to eastern India - Bihar, Jharkhand and Assam.
The second most polluted city in India is Brynihat in Assam.
Very close to Jharia’s air quality, this city has a PM10 concentration of 257 μg/m3.
The next three cities in the list of ‘top 5’ belong to Bihar, starting with Saharsa with a PM10 concentration of 250 μg/m3. It is followed by Katihar with a PM10 concentration of 227 μg/m3, and Samastipur with PM10 concentration of 220 μg/m3.
Interestingly, the city that is on everybody’s lips when air pollution is mentioned – Delhi – is not part of the top 5 list. The city had an average PM10 concentration of 205 μg/m3 as per data published by Commission for Air Quality Management in NCR and Adjoining Areas (CAQM) in 2023.
The reason for the high reading in these eastern Indian cities was not disclosed by the ministry, but is likely related to the extensive mining and industrial activity in the region.
For example, Jharia is reportedly the “heartland of India’s coal industry” with more than 20 underground mines and several large open-cast mines. Jharia has also been witnessing persistent fires in the coal mines which have claimed several lives and have been posing threat to the residents of the town.
Byrnihat in Assam, the second in the list, is home to several industries, which has ensured the hill city a place in the list. No. 3 on the list, Saharsa, is also home to several types of industries including brick manufacturing, jute and paper.
So, just how dangerous is PM10?
According to the US Environment Protection Agency (EPA), the standard for average exposure to polluted air particles over 24 hours is 150 micrograms per cubic meter. The EPA standard for average annual exposure is 50 micrograms per cubic meter.
At moderate PM10 levels i.e, 51-100 μg/m3 over 24 hours the polluted air can cause breathing discomfort to people with lung diseases such as asthma. It can also cause discomfort to the general public.
Meanwhile, at higher than the standard levels, i.e, 101-150 μg/m3 over 24 hours, the polluted air can lead to respiratory symptoms and breathing difficulty in people with lung disease, older adults and children.
At very unhealthy levels, 151-250 μg/m3 over 24 hours, the polluted air can lead to significant increase in respiratory effects and even premature mortality in people with lung disease and older adults. In addition to this, living in cities with highly polluted air can significantly increase respiratory diseases in the general public.
Long term exposure to PM10 is also known to cause lung cancer.