While Air Quality Improves in Other Major Cities, These Two Cities Worse in 2018

New analysis from Smart Air finds that 2018 was a good year for air quality for India’s major cities. Air quality was flat or down in three of five cities—Delhi, Hyderabad, and Chennai.



Yet two cities saw air pollution rise significantly. PM2.5 pollution was up 17% in Kolkata, exceeding nine times the World Health Organization annual limit of 10 micrograms per cubic meter.


Kolkata Air Quality West Bengal PM2.5 Pollution


Air quality worsened in Mumbai too. Particulate levels rose 15% year over year in Mumbai.


Mumbai India Air Quality Maharashtra


Analysis by month shows that Mumbai’s worsening air quality came mostly from unusually polluted summer months.


Mumbai Monthly Air Quality


In Kolkata, 2018 air quality was worse mostly in the winter months.


Kolkata Monthly Air Quality


Microscopic Particles in the Air


The analysis is based on PM2.5 pollution, particles smaller than 2.5 microns in diameter that can penetrate deep into the lungs and even enter the bloodstream. Studies have shown that PM2.5 raises blood pressure, inflammation, and rates of heart attacks and strokes.


PM2.5 Pollution Air Quality


The data comes from the US Embassy and consulates in India’s major cities. This data is open for researchers, although it has limitations. It comes from only one pollution sensor in each city, and pollution can vary between neighborhoods.


Poor Air Quality Mumbai


Read more: Check out in-depth air quality reports for the following cities:


Protect Yourself

Despite the harms of PM2.5, studies have found that wearing masks prevents physiological harm to the body. In addition, placebo-controlled studies of air purifiers have found that removing particulate in the home has positive effects on blood pressure, inflammation, and immune response.


Smart Air provides empirically backed, no-nonsense purifiers and masks to help air-breathers protect themselves and their family. Smart Air is a certified B Corp founded to publicize the simple science behind air purifiers and masks, thereby lowering the cost of breathing clean air.

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Smart Air is a social enterprise that creates simple, no-nonsense air purifiers and provides free education to protect people’s health from the effects of air pollution. We are proud to be the only certified B-Corp dedicated to fighting air pollution.