Fact check: Is there no link between air pollution and poor health, as Union minister claims?

India’s environment minister of state, Ashwini Kumar Choubey, said in August that there is no conclusive data in India to establish a direct correlation between health and air pollution. But research and studies show, and experts confirm, that such evidence does exist.

To a question in Parliament on August 8, on whether any study has been conducted about the adverse health effects of pollution from transport and industrial clusters, and government and private power plants, Choubey, Minister of State for Environment, Forests and Climate Change, said: “Air pollution is one of the factors for respiratory ailments and associated diseases. However, there is no conclusive data available in the country to establish direct correlation between health and air pollution. Health effects of air pollution are a synergistic manifestation of factors, which include food habits, occupational habits, socio-economic status, medical history, immunity, heredity, etc., of the individuals”.

This claim is partly false: The claim on the lack of conclusive data to establish a correlation between health and air pollution is false. Several studies, including one in 2012 by the Central Pollution Control Board, which falls under the Ministry of Environment, Forests and Climate Change, has found that exposure to air pollution increases the risk of impaired lung function and cancer in a study of residents of Delhi.

The second part of the claim is true, and the health effects of air pollution depend on several factors, the Central Pollution Control Board study found.

The minister has made similar claims in the past as well: in response to a question asked in parliament on July 18, on deaths due to pollution, Choubey replied that “There is no conclusive data available to establish a direct correlation of death/disease exclusively with air pollution.” He had also made the same claim in August 2021 and in March 2021.

Lungs and other organs susceptible to damage from air pollution: Experts

There is a correlation between air pollution and poor health, which means that as certain diseases grew so did air pollution.

For instance, Choubey’s colleague and Minister of State for Health and Family Welfare Bharati Pravin Pawar told Parliament on December 10, 2021, said that an Indian Council of Medical Research multisite study found that an increase in pollution levels was associated with increase in number of patients attending emergency rooms due to respiratory issues, with the effect more pronounced in children.

Respiratory symptoms (such as sinusitis, sore throat, sneezing, dry cough, etc.) were 1.7 times more prevalent in Delhi than in the rural areas of West Bengal, found the 2012 study by the Central Pollution Control Board to assess air pollution-related respiratory symptoms among the residents of Delhi. The study also found that more residents of Delhi showed reduced lung function compared to those of rural West Bengal.

However, is that enough to conclude that as air pollution increases so do respiratory diseases? Studies, including in India, use a variety of statistical methods to conclude whether health impacts can be attributed to air pollution.

The study comparing Delhi and West Bengal, for instance, tested sputum samples and found they were more “heavily loaded with particles resulting in increase of cell size indicating high particulate [pollution] exposure.”

About 18% of all deaths in India (1.7 million) were attributable to air pollution, according to a 2020 study by the Global Burden of Disease Initiative, supported by the Indian Council of Medical Research and the Public Health Foundation of India. The number of deaths caused by outdoor ambient air pollution increased by 115% between 1990 and 2019, found the same study. In terms of poor health, India lost 53.5 million years of life in 2019 to disability caused by air pollution.

The study used data on PM2.5 (fine inhalable particles with a diameter about one-thirtieth the diameter of human hair) obtained from satellites, which were validated using data from monitoring stations from the Central Pollution Control Board’s ground stations. The death rates were modelled for 28 Indian states, Delhi, Jammu & Kashmir and Ladakh and the union territories of Andaman and Nicobar Islands, Chandigarh, Dadra and Nagar Haveli, Daman and Diu, Lakshadweep, and Puducherry.

FactChecker asked Dr Balram Bhargava, former director of the Indian Council of Medical Research and one of the speakers at the press conference where the findings of the GBD study were presented, about the data used in the study. This story will be updated when he responds.

“Air pollution definitely causes health issues. While it is commonly believed that it causes diseases of the lungs, air pollution also causes asthma and aggravates it, it increases the risk of heart disease, diabetes and stroke,” said Dr Prabhakaran Dorairaj, cardiologist and epidemiologist at the Public Health Foundation of India.

Globally, 7 million people died prematurely because of air pollution in 2019, as per the United Nations Environment Program. Of all the health outcomes of pollution, it is ‘most strongly linked’ to stroke, ischaemic heart disease, chronic obstructive pulmonary disease, lung cancer, pneumonia and cataract, according to the World Health Organization.

Another way to link air pollution to health impacts is by looking at what the pollutants are and whether those have been linked with diseases. PM2.5, PM10 (particles with a diameter, about one-seventh of human hair)and SOx, monitored by the Central Pollution Control Board, are known to increase the risk of cancer in humans, and are also present in polluted air.

We have reached out to the environment minister for comment on his response to the Parliament and on studies that show a link between air pollution and health impacts in India. We will update the story when we receive a response.

Air in many Indians cities is routinely worse than Indian standards

The link between air pollution and health becomes important for India because in over 70 of the 180 cities for which air quality is monitored, the air quality was categorised as “poor” [Air Quality Index, AQI over 200], “very poor” [AQI over 300] or “severe” [AQI over 400], based on Central Pollution Control Board AQI bulletin on November 29. An AQI over 400 means that the concentration of pollutants in the air “affects healthy people and seriously impacts those with existing diseases”.

The Central Pollution Control Board sets limits for concentration of SO2, NO2 and PM10 and PM2.5 in a 24-hour period as well as an annual arithmetic mean.

In 2019, the level of PM10 exceeded the limit set by the Central Pollution Control Board in 569 0f 731 sites for which data were available, as per the board’s report. The level of PM2.5 exceeded the permissible limit in 138 of the 197 sites for which data was available, according to the same report. SO2 was found to be within limits for 714 of 787 sites for which data were available.

Further, these limits are higher than the permissible limits set by the World Health Organization (WHO). For instance, for SO2, the limit is 80 microgram/cubic metre in a day, which is twice the permissible limit set by the the World Health Organization.