New Delhi: At a time when uncertainty on the link between air pollution and Covid-19 transmission and infection looms large over India, it has emerged that air pollution is now the largest risk factor for deaths among all health risks in the country and a high risk factor for newborns.
According to State of Global Air (SOGA) Report, 2020, long-term exposure to outdoor and household air pollution — which led to strokes, heart attacks, diabetes, lung cancers, chronic lung diseases and neonatal diseases — contributed to 16,67,000 deaths in India in 2019.
Air pollution is thus now the largest risk factor for deaths among all health risks, the report revealed on Wednesday.
The 2019 data on the burden of different diseases that air pollution contributes to showed that about 60 per cent of deaths were caused due to chronic obstructive pulmonary disorder (COPD), 43 per cent due to lower respiratory infection deaths, 35 per cent due to ischemic stroke and 32 per cent due lung cancer and ischemic heart disease. The total number of deaths mentioned in the report refers to the number of deaths in a given year attributable to air pollution that likely occurred earlier than would be expected in the absence of air pollution.
What’s more worrisome is that air pollution has also emerged as one of the biggest killers among infants globally and in India. The report stated that nearly 21 per cent or 1,16,000 neonatal deaths India from all causes were attributable to ambient and household air pollution in 2019. There is growing evidence that indicates that particulate air pollution exposure during pregnancy is closely linked to low birth weight and pre-term birth.
“An infant’s health is critical to the future of every society, and this newest evidence suggests an especially high risk for infants born in South Asia and sub-Saharan Africa,” said Dan Greenbaum, President of Health Effects Institute.
Studies of Indian government have shown in the past that one out of every eight deaths in India is attributable to air pollution; over half of the 12.4 lakh deaths in India attributable to air pollution in 2017 were in persons younger than 70 years.
“Addressing impacts of air pollution on adverse pregnancy outcomes and newborns health is really important for low and middle-income countries, not only because of the high prevalence of low-birth weight, preterm birth, and child growth deficits but because it allows the design of strategic interventions that can be directed at these vulnerable groups,” said Dr Kalpana Balakrishnan, an air pollution and health expert who was not involved with the study.
Rising Trend of Air Pollution in India and Covid-19
Even as globally PM2.5 exposures declined slightly between 2010 and 2019, notably in Southeast Asia, East Asia and Oceania, South Asia and Africa have seen a rising trend. In India, the population weighted average PM 2.5 exposure increased by 6.5 micrograms/metre cube (ug/m3). This rise was the third highest behind Bangladesh and Nigeria. Meanwhile, a reduction was seen in China, Turkey, Brazil, Mexico and Iran.
The report said that ambient particulate matter pollution and ozone pollution were two of the biggest contributors to deaths across the world. In India, over the last decade, 3.73 lakh deaths were linked due to exposure to high PM 2.5 levels and 76,500 deaths were linked to high ozone exposure. Even though there is no clear evidence which indicates that air pollution helps in greater transmission of the SARS-CoV-2, it is well established through studies that those suffering from respiratory ailments are at a greater risk to new infections due to a weaker immune defence.
A silver lining for India is the gains it has made in the reduction of household and indoor air pollution, especially in the rural areas. One of the key reasons attributable to this reduction is the government’s scheme to distribute cooking gas cylinders to cut out dependence on solid fuels such as firewood. China reduced the percentage of its population exposed to household air pollution from 54 per cent to 36 per cent, while India reduced its percentage from 73 per cent to 61 per cent over the last decade.
How is Burden of Death Estimated?
As part of the Global Burden of Disease project, estimation of burden of disease is done with a systematic evaluation of scientific evidence and whether it is strong enough to attribute a given health outcome or cause of death due a specific pollutant, the report said.
Mathematical functions derived from epidemiological studies that indicate different levels of exposure to the increased risk of death, estimations of population exposure to PM 2.5, ozone and household air pollution, country-specific data on disease and deaths and population data are some of the tools used to estimate burden of disease.