Mumbai air quality improved 2% in 2021, compared to the previous year. These higher air pollution levels push Mumbai’s annual PM2.5 average to more than eight times the World Health Organization’s annual limit of 5 µg/m³. Let’s dive into what trends we see throughout the year with Mumbai air quality and how Mumbai compares with the rest of India.

Mumbai Air Quality: 2020 vs 2021

Mumbai’s 2021 PM2.5 air pollution levels remained relatively unchanged compared to 2020. With the 2% improvement, Mumbai still averaged 43 micrograms of PM2.5 air pollution in 2021.

Mumbai Monthly Air Quality

Mumbai’s PM2.5 levels started 2021 at higher levels than in 2020. Breaking down the data by month, air quality in 2021 tracked 2020 closely. As usual, the air quality during the winter months was much worse compared to the summer months in Mumbai.

Trends in Mumbai’s Air Quality

In 2021 Mumbai saw some improvement in air quality during the COVID-19 lockdown. The months of July and August saw an improvement in PM2.5 levels mainly due to the monsoon season in Mumbai. The data shows that wind blows pollution away and lowers overall air pollution levels. But thereafter, Mumbai’s pollution levels start peaking during winter with PM2.5 typically beginning to rise to start in October and remaining high until March of the next year.

Mumbai’s Air Quality Compared to Other Cities in India

Mumbai’s air quality is now far worse than Bangalore and Chennai’s after this year’s worsening of PM2.5.  The marginal improvement this year means Mumbai is still third in terms of the worst air pollution among all of India’s major cities. Delhi — by far the most polluted city in India — still has pollution levels over two times higher than Mumbai.

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

The data came from the US Consulate in Mumbai. It is open for researchers, although it does have its limitations. The data comes from only one pollution sensor in the city, which means a risk of the data not being representative of the whole of Mumbai. It’s highly possible that pollution levels vary between Mumbai’s different neighborhoods. If this was the case, then pollution levels in different neighborhoods could have different pollution levels.

Protect yourself:

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

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