During the early months of 2020, when the whole world was navigating the onset of the covid-19 pandemic, nations around the world implemented strict lockdowns with the aim of stemming the spread of the novel coronavirus.
These lockdowns also had a direct effect on the air quality. Local and global travel was shut down, industrial activities were brought to a halt, and vehicular emissions dropped. Naturally, there were substantial reductions in concentrations of pollutants such as nitrogen dioxide (NO2) and, in some cases, slight reductions for other pollutants such as PM2.5. All of these are rising again as economic activity resumes.
But what happened in 2019? The State of Global Air 2020 report, released on 21 October, reveals that air pollution was the fourth leading risk factor for early deaths worldwide in 2019, behind only high blood pressure, tobacco use, and poor diet. There is worrying news for India as well. Long-term exposure to ambient and household air pollution contributed to over 1.67 million annual deaths from stroke, heart attack, diabetes, lung cancer, chronic lung diseases, and neonatal diseases, in India last year, the report adds, making it the highest health risk in the country.
For the first time, the State of Global Air report — which is published annually by the Boston-based Health Effects Institute and the Institute for Health Metrics and Evaluation’s Global Burden of Disease project — has included the effect of air pollution on adverse birth outcomes. Shockingly, the report revealed that outdoor and household particulate matter pollution contributed to the deaths of more than 116,000 Indian infants in their first month of life in 2019.
One of the most difficult challenges in cutting down air pollution is the ambient PM2.5 levels. These are particles that measure less than 2.5 mm in diameter and can cause life-altering damage to the human body by going deep into the lungs and even the bloodstream. As the report explains, countries in Asia, Africa, and the Middle East continue to experience the highest levels of ambient PM2.5.
Global patterns reveal that India had the highest population-weighted annual average PM2.5 exposures in 2019 (see chart 1) and 90% of the world’s population was exposed to PM2.5 concentrations that exceeded the World Health Organization’s air quality guideline of 10 micrograms per cubic metre. Understanding the concentrations that individuals actually experience — their exposure — is crucial to estimating the burden of disease associated with PM2.5 pollution, the report adds.
A further look at global trends shows that ambient PM2.5 exposures have declined slightly from 2010 to 2019 in some regions (see chart 2). For instance, 20 of the world’s most populous countries account for 70% of the global population. And out of these, 14 have witnessed a decline in their annual average PM2.5 exposures since 2019. But countries with some of the highest exposures last year —Bangladesh, Pakistan and India — continue to see an increase.
The report comes at a crucial juncture for India in 2020 as it continues to handle the covid-19 pandemic, along with the onset of peak pollution season in parts of north India. While the country did enjoy some rare clean air days earlier this year, air quality has already dipped in major regions like Delhi-NCR.