Air Quality in Delhi – A Threat to Lung Health

Air Quality in Delhi – A Threat to Lung Health

Air Quality – There was a public health emergency in India just months before the one that is now gripping the world. In November 2019 schools were closed, people stayed at home, construction stopped and roads were nearly deserted. Flights were diverted from the epicentre – the city of Delhi. This health emergency, like the current one, involved the breathing in of potentially lethal particles. But this previous emergency was unlike COVID-19 in many other ways. Nothing about it was natural. It was completely manmade. And nowhere was safe.

Outdoor Air

The manmade pollution seeped into every house and office, every nook and cranny, and effected the air entering the lungs of every one of Delhi’s 40 million people. The episode in Delhi in November was triggered by crop stubble burning by farmers in the surrounding states combined with high humidity, light rains and low wind, but all year round, Delhi suffers from noxious air. The main culprit is fossil fuel – factories, transportation, cooking, industry, heating, cooling all require energy and in India the main source is fossil fuel, usually coal. Bad air is not a new phenomenon for Delhi or for many other cities in India. In fact, Delhi doesn’t usually feature in the top most polluted cities in India- the tops spots are usually inhabited by Kanpur, Faridabad, Varanasi and Gaya. India ranks pretty poorly for air pollution in general with 21 of the world’s 30 cities with the worst air pollution.

Despite being fundamentally different, the two crises are also inherently linked- new studies are showing that the death rate from Covid19 is higher in areas of worse pollution.

“People that have been breathing polluted air for a long time, we know that long term exposure to fine particulate matter increases inflammation in the lungs and potentially in the cardiovascular system. If on top of that, these individuals are affected by COVID-19, then its not surprising given that given that they’ve already been impacted by fine particulate matter, that they might respond with much worse health outcomes than someone who lives in a clean air county,”  says study author Dr. Francesca Dominici.

In other words, those that live in areas of high pollution are more likely to have respiratory disease and so makes them more vulnerable to COVID-19. We may be living through a pandemic but today is Earth Day and the UN has reminded us not to forget the ‘deeper environmental emergency’ facing us all.

In Delhi, when the unbearable pollution had reached near record levels, the AQI recorded was nearly 900- it made Delhi the most polluted city in the world. Air Quality Index or AQI measures the concentration of PM 2.5 levels –the dangerous fine particles of less than 2.5 microns that can enter the bloodstream and penetrate the lungs and heart. Anything above 400 on the AQI poses a risk for people with respiratory illness and can also affect even those with healthy lungs. On days like this, healthy people will experience reduced endurance in activities and may also show symptoms of lung distress. Other illnesses may be triggered in healthy people and healthy individuals should avoid outdoor activities.

Lung Disease in India

So if pollution of this level effects healthy people, what about people who already have respiratory disease? India has one of the highest rates of respiratory disease in the world. Chronic obstructive lung disease (COPD), asthma and tuberculosis are the main issues. India has the world’s highest number of tuberculosis cases. In 2016 there were 2.7 million new cases and 423,000 TB patients died – that’s a third of the worlds TB 1.4 million death toll.

According to the WHO, between 15 and 20 million people in India have asthma. A rough estimate indicates its prevalence between 10% and 15% in 5-11 year old children. At present it is estimated that 25% of population suffers from allergies in India.

Indoor Air

face mask India poor airThe advice to people with respiratory disease on bad air days is to stay indoors. But staying indoors to avoid toxic outdoor air may not serve the purpose anymore as pollutants have now entered homes. It’s not just outdoor air that’s polluted, indoor air is too. A new study has revealed that air inside homes in Delhi have become unsafe with high levels of PM2.5, carbon dioxide and other pollutants, despite keeping doors shut.

This poor indoor quality is hugely damaging to those with respiratory disease. Among the many triggers for asthma is polluted air. Combine this polluted air with other indoor triggers- dust mite, Volatile Organic Compounds (VOCs), food, pets, mould and the home becomes toxic for those with asthma. Many of these indoor triggers are avoidable but a lack of education means that millions of people are not fully aware of this.

dust miteDust mite is the most common avoidable trigger of asthma and allergies in the home. These tiny insects live in the dust that builds up in the home – in bedding, carpets, soft toys, cushions and furniture – and it is the droppings of these mites that causes the problem. Some simple but small changes can make big differences in the home. For example, dust mite barriers and pads for mattresses and pillow cases help reduce exposure to dust mite. Regular vacuuming with a vacuum cleaner with a HEPA filter will reduce dust and therefore reduce dust mite.

Air purifiers can help clean the air by reducing allergens, chemicals and pollutants. Chemicals are produced by all sorts of household products, bedding and furniture, so by choosing products that produce less chemicals, triggers are reduced.

Recent studies have shown that poor air quality may also be associated with the catastrophic levels of TB in India. A 2014 study published in the International Journal of Tuberculosis and Lung Disease showed that indoor air pollution was independently associated with TB. Other studies have also shown this link and it is thought to be because poor air interferes with the immune cells necessary to fight against TB. Yet further studies have indicated a link between poor air quality and drug resistance in TB patients.

Healthcare in India

Quality of life, and quality of healthcare, varies hugely in India. The divide between rich and poor is vast and there is a wide gap between healthcare facilities for rich and poor. All forms of medications are available in pharmacies but they are expensive and just not affordable for many. This divide extends to education so asthma is still considered a stigma to many and as a result, families try to conceal the disease. One study showed that only 39% of parents of asthmatic children accepted the diagnosis of asthma in their child. Compliance with inhaler treatment tends to be poor so despite a readily available, though under-utilised, ‘guidelines for diagnosis and management of bronchial asthma’ patients tend to only treat their asthma when they are symptomatic. Many believe the medictaion to be habit forming. In fact, in that same study, only 13% of patients were using inhalers at home. Many symptomatic individuals seek treatment from the non-formal health practitioners of alternative medicines and faith healing, who often prescribe harmful and toxic ‘cures’.

Indian medical clinic lung disease
India’s healthcare system is vast and disparite. It is a universal system but is primarily administered by individual states, which means there is huge discrepancy in the quality and coverage of treatment throughout the country. In the cities, ultra-modern glass buildings house the hospitals and high tech healthcare facilities for the well-to-do. At the other extreme, in remote rural areas, there are physician shortages in ramshackle clinics that are few and far between. Lack of adequate coverage by the health care system across India means that those that can afford to turn to private healthcare providers. Insurance is available and can be provided by employers but the majority of Indians lack health insurance and struggle to afford treatment and medicines. In February 2018 the Government announced that it is planning free health insurance to cover treatment costs for 100 million low income families.

Regular education programmes and initiatives are slowly increasing acceptability of inhaler treatment and thankfully, due to these education programmes, asthma mortality in India is slowly falling. However, a third of the global health loss from chronic respiratory diseases still occurs in India. DALYs (Disability adjusted Life Years) measure the sum of the years of potential life lost due to premature mortality and the years of productive life lost due to disability. The DALYs per person with COPD and asthma are higher in India than most countries. There are a number of reasons for this – late diagnosis and management, underdiagnosis, insufficient awareness about the disease, the perception of stigma around the use of inhalers, lack of awareness of triggers and allergens. Clearly, policy approaches need to be improved but also targeted so that the vastly different attitudes across the states can be changed.


The COVID-19 pandemic is nothing less than catastrophic for the global community, but it has provided an opportunity to teach us about the value of healthy air and healthy homes and its impact on our lungs. India’s 1.3 billion people have been put on lockdown and with this, all factories, markets, shops, places of worship have closed. Most public transport has been suspended and construction work has stopped. The welcome side effect of this is a dramatic improvement in the air quality. People across India have enjoyed blue sky days the like of this generation have not seen before. The possibility of a cleaner, healthier future has been glimpsed and a chance to change to more sustainable fuels and renewable energy surely can’t be missed. At the very least, it’s an opportunity to try to reach existing targets. As people are confined indoors, the indoor environment has never been so important. The reduction of triggers for asthma and allergens in the home is achievable and maintainable by educational programs. Simple changes can have a huge effect on those that are impacted by respiratory disease.



Medical & Lifestyle Author Dr Anna O'Donovan

Medical & Lifestyle Author Dr Anna O’Donovan

About Dr. Anna O’Donovan – Medical & Lifestyle Author 

Anna is a mum of three children, one with allergies, and she suffers from allergies and asthma herself. She is a qualified doctor and worked as a General Practitioner and as a dentist for a number of years. She is also an award-winning author.


Key Words

air quality, indoor air quality, pollution, outdoor air, asthma, COVID-19, healthy, chemicals, allergies, dust mite, bedding, air purifiers, lung health, lung disease, TB, tuberculosis


References and further reading

Environmental International :Ambient air pollution exposures and risk of drug-resistant tuberculosis Click here

CNN :The world’s largest coronavirus lockdown is having a dramatic impact on pollution in India Click here

Not just outdoor, indoor air in Delhi polluted too: Study Click here

The Lancet: The burden of chronic respiratory diseases and their heterogeneity across the states of India Click here

RTE : Air pollution at ‘unbearable levels’ in India Click here

Trapped and helpless: How families are fighting Delhi’s pollution horror Click here

India Today : Delhi struggles to breathe but not even in top 10 polluted Indian cities Click here



Related Internal Links






By |2020-09-29T11:36:13+00:0028 April 2020|Tags: , , , , , , , , , , , |Comments Off on Air Quality in Delhi – A Threat to Lung Health