Pune, Western Maharashtra emerge as air pollution hotspots in India

Air pollution, particularly levels of Nitrogen Dioxide and Sulfur Dioxide, rose sharply in towns and cities in Western Maharashtra in 2016, according to data from the National Air Quality Monitoring Programme of India.

Though 2016 saw a worsening of air quality across the country, the deterioration was marked and noticeable in Western Maharashtra.

Arranged by the levels of Sulfur Dioxide in the air, the top four cities in India belongs to Western Maharashtra, as does six of the top seven.

Similarly, for Nitrogen Dioxide, the top three were in Western Maharashtra in 2016.

It is only in the last criteria tracked by National Air Quality Monitoring Programme — Particular Matter levels — that these Maharashtrian cities did not lead the nation.


Pune and the nearby town of Pimpri-Chinchwad beat all other cities in India when it came to Nitrogen Dioxide and Sulfur Dioxide pollution, with Mumbai suburb Kalyan Dombivali and Nashik and Aurangabad not far behind.

However, on a positive note, Sulfur Dioxide levels in these cities, while two to three times as high as that in most other cities in India – are within the safe limit set by the Central Pollution Control Board.

However, it was a different story on Nitrogen Dioxide. Levels of NO2 in Pune and Pimpri Chinchwad are already nearly double the safe limit.

Both Sulfur Dioxide and Nitrogen Dioxide are known to cause respiratory diseases, while NO2 is also known to cause problems related to the immune system, trigger inflammation and even impact the health of the heart.

Surfur Dioxide too is implicated in causing breathing difficulties and even preterm birth in humans.

The primary source of NO2 is internal combustion engines of vehicles, while SO2 is released by both the of Sulfur-containing fuels, such as petroleum and coal. In India, many power plants burn sulfur-containing coal to produce electricity.

Besides vehicular engines — which become hot enough to combine atmospheric Nitrogen and Oxigen into Nitrogen Oxides — power stations also contribute to the generation of Nitrogen Dioxide.

Western India, particularly parts near Mumbai, are home to many big industrial units. Many factories have relocated from Mumbai to nearby areas like New Bombay, Kalyan-Dombivali as land costs have risen in Mumbai.

Besides, Pune is home to many big office buildings which burn diesel to generate power.

Unlike Mumbai — which is a coastal city and gets help from sea breeze to dissipate the pollutants — the towns further inland — such as Pimpri Chinchwad, Pune and Dombivali — do not get the help of sea breeze to dissipate these pollutants.

As a result, while Mumbai has a NO2 reading of 48, Pune had a reading of 85 – over twice the safe limit of 40 microgram per cubic meter.

Pimpri-Chinchwad had a reading of 82 and Kalyan Dombivali recorded 74.

Delhi, which often gets rapped for being the most polluted city in India, had a reading of 65 in 2016.

These numbers are the averages calculated over a period of one year, and the levels of these chemicals would certainly be higher in certain days and months of the year depending of the prevalence of wind.


Another worrying aspect of the high readings in Western Maharashtra is the fact that things here are going from bad to worse.

The rise in pollution levels has happened in a matter of 2-3 years.

In 2014 for example, Pune had a NO2 reading of just 45. This jumped to 62 in 2015 and 85 in 2016.

Similarly, Pimpri Chinchwad went from 41 in 2014 to 52 in 2015, and 82 last year.

In contrast, a city like Delhi — where awareness of air pollution is much higher — saw NO2 levels stabilize. Delhi had a reading of 61 in 2014 and 65 in 2015 and 2016.

Another city that saw a big easing is Kolkata, which went from 70 in 2014 to 56 the next year and 50 in 2016.

Mumbai too remained largely stable, with readings of 20, 25 and 25 during the three years from 2014 to 2016.

The same worsening trend can be seen in case of Sulfur Dioxide too. Though no city in India has crossed the limit of 50 micrograms, at current rate, Pimpri Chinchwad and Pune could be the first to get there.

SO2 levels in Pimpri Chinchwad almost doubled to 40 in 2016 from 23 in the previous year, while Pune’s reading increased to 34 from 23 in 2015.


The increase in air pollution in these cities was not confined to chemicals only.

Dust particles, as measured by the amount of particles of the size 10 micrometer and less, has been showing an equally alarming rise, though they are not as bad levels seen in North Indian cities yet.

Pimpri Chinchwad, for example, recorded a rise of 50% in its PM10 reading in 2016 to 152 from 102 in the previous year and 93 in 2014. This is 2.5 times the annual upper limit of 60 micrograms.

Similarly, Pune also saw a 33% increase in PM10 levels to 132 from 99 in the previous year and 92 in 2014.

In fact, the biggest increase in PM10 pollution in India over the last three years has been recorded at the nearby city of Nashik, where levels have increased from 72 in 2014 to 162 in 2016.