Not just lungs, Delhi's toxic air is attacking your heart too: Alarming study finds 2% rise in CVD risk for every PM2.5 spike

A recent pilot study published in the journal Discover Public Health by Springer Nature has found a clear short-term increase in cardiovascular emergencies in Delhi following spikes in air pollution. Air pollution and extreme heat are significant environmental risk factors contributing to cardiovascular disease (CVD) morbidity and mortality in changing climate, the study said. The study conducted in 2021 showed that hospital admissions increased by 1.8%, 1.2% and 2% respectively each time the AQI, PM10 and PM2.5 levels rose by 10 units in the city. In contrast, a similar analysis carried out in the hill station of Shimla did not reveal any such trend. Titled “Piloting surveillance of environmental risks and cardiovascular events in Delhi and Shimla, India, 2021”, the study was recently published in the journal Discover Public Health by Springer Nature, reports TOI's

The study revealed that cardiovascular events in Delhi increased by 1.8% for every 10-point rise in AQI at a one-day lag. Admissions also rose by 1.2% and 2.0% for similar increases in PM10 and PM2.5, respectively. "We analysed 41,436 eligible admissions, including 11,494 CVD events in Delhi and 3,849 in Shimla. In Delhi, CVD events increased by 1.8% (95% CI:0.5%-3.05), 1.2% (95% CI:0.1%-2.3%) and 2.0% (95% CI:0.7%-3.2%) per 10-unit increase in AQI, PM10, and PM2.5, respectively at one-day lag. Shimla showed inconsistent, non-significant associations," the study revealed.

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Delhi pollution deadlier than you think

The study analysed hospital admissions and deaths related to cardiovascular disease (CVD) alongside daily air quality and weather data in the Delhi and Shimla between January and July 2021. Researchers examined more than 41,000 hospital admissions across selected tertiary care hospitals, identifying over 11,000 cardiovascular events in Delhi and nearly 3,900 in Shimla. In Delhi, the analysis found that heart-related emergencies rose sharply within a day of an increase in air pollution levels.


Across both cities, myocardial infarction and coronary artery disease were the most commonly reported conditions. The study—conducted by researchers from the National Centre for Disease Control, the India Meteorological Department and Safetynet, New Delhi—also highlighted notable differences in patient profiles. Patients in Delhi were generally younger and more likely to report physical inactivity, high-salt and high-fat diets, hypertension and psychological stress, while tobacco use and the use of solid fuels for cooking were more prevalent in Shimla. The researchers also found no significant difference in COVID-19 status between patients in the two cities during the study period.

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"Alcohol use, physical inactivity, specific diet intake, pre-existing hypertension and reported psychological stress were significantly higher in patients from Delhi. The proportion of tobacco smoking and use of solid fuel for cooking were higher in Shimla.... Among patients using tobacco in any form, 98% of patients from Shimla reported smoking a bidi/cigarette. Almost 67% of patients from Shimla reported using solid fuel or kerosene as the primary fuel for cooking, whereas 98% of Delhi used gas or electric appliances," the study said.

It also pointed out that the Covid-19 status was not significantly different. "We noted Delhi's average daily particulate matter (PM10 and PM2.5) concentrations exceeded National Ambient Air Quality Standards (NAAQS) in the first half of 2021, despite the Covid-19 outbreak. For Shimla, the average daily PM10 exceeded standards for three months in early summer."

(With TOI inputs)