Asthma in India has a disproportionately high death rate, representing three times greater mortality and over two times greater Disability-Adjusted Life Years (DALYs) than the global share of the asthma burden. While asthma is recognised by a multitude of symptoms including shortness of breath, wheezing, coughing, and tightness in the chest, in the wake of rising temperatures, unprecedented heat, and the relentless progress of climate change, it is becoming an underappreciated threat to respiratory health, especially for those who already have asthma. Aside from the unpleasantness of the blistering heat, environmental changes can aggravate asthma symptoms and, worse, seem to be causing new cases among healthy people.
Patients with severe asthma have an enhanced sensitivity of their airways to dry air. This dryness causes a reduction in water content of the airway, which evokes an inflammatory response. This inflammation, in turn, makes the airways narrowed, a process also referred to as airway constriction, which further restricts breathing. The already vulnerable respiratory system cannot handle the additional load of intense heat and therefore, has more episodes of asthma attacks.
The scenario is further compounded by the synergistic effects of increasing temperatures and intensifying air pollution – a direct fallout of urbanisation and industrialisation driving climate change. This causes injury to the epithelial cells of the airway, the defensive lining of the respiratory tract. This makes the respiratory system more vulnerable to high temperatures, and also enhances the allergenicity of current pollutants. The twin burden of heat and pollution results in a more reactive and susceptible respiratory bed.
Asthma-like symptoms in previously healthy individuals
Clinicians are now seeing an increase in patients with asthma-like symptoms who have no previous history of respiratory ailments. Although severe temperatures can cause mild respiratory symptoms even in normal individuals, the growing frequency and duration of heat waves, combined with increased levels of allergens, could be tipping some over an edge, precipitating the onset of asthma.
Interestingly, when asked about new or unforeseen environmental irritants within their practice that were not widespread a few years ago, there was a negative response. This indicates that as the intensity and effect of current irritants intensify, completely new triggers are perhaps not yet the main issue.
There are particular groups of patients at risk of asthma exacerbations when the weather is very hot or unstable. As medical officers have pointed out, the extremes of age: very young children and the old are especially at risk. Their physiological reserve and regulatory capacity might be less, and so they are less capable of coping with acute or sustained temperature stress.
In terms of geographical patterns in weather-related asthma severity, the general opinion is that the risk is more or less similar in urban and rural settings, mainly as a result of the general influence of industrialisation and related pollution. Although urban areas tend to have greater levels of pollutants, rural settings may also be influenced by agricultural activities and long-range transport of air pollutants.
Proactive steps and preventive strategies for asthma patients
With these escalating dangers, proactive measures are important for asthma patients on extremely hot or smoggy days. Physicians advise proper hydration to offset the dehydrating properties of dry air. Staying indoors during the most intensely hot part of the day is also necessary to avoid heat and pollutants. Wearing a clean mask can serve as an immediate physical shield against airborne allergens. Importantly, patients need to follow their physician’s instructions carefully regarding the use of regular inhalers to control their baseline inflammation and keep quick-relief medication handy.
For those who do not have asthma but have seasonal respiratory symptoms that may be climate-related, the recommendation is slightly different. Although routine preventative inhaler use is not usually advisable in the absence of a proper asthma diagnosis, seeing a healthcare provider to determine specific triggers and create an individualised management plan is recommended. This may involve such strategies as avoiding known allergens or taking over-the-counter medication for mild symptoms.
Long-term health risks and the need for climate action
The long-term health impacts of deteriorating climate trends are becoming a major concern. Physicians are highlighting the imperative for community action to reverse climate change. Actions like reforestation to enhance air quality and fostering a healthier environment are crucial. A priority of making a “breathful India” through sustainable environmental management is viewed as vital to protect the respiratory health of all individuals. Finally, a focus on the underlying causes of climate change is critical to protecting vulnerable groups and helping everyone breathe easily and safely in the future.
This is especially significant, as India has a heavy asthma burden. Estimates are difficult to get, but the Global Burden of Disease study (1990-2019) has estimated approximately 34.3 million individuals with asthma in India, which represents about 13.09% of the worldwide burden. A high proportion of asthma cases in India are not diagnosed. It has been estimated by experts that more than 80% of the cases of asthma in India may go undiagnosed, and this can progress over a period of time. There are differences in prevalence among regions and populations. There is evidence of increased prevalence in rural locations and in females. Childhood asthma is a significant reason for emergency department visits, hospitalisations, and school absence.
Higher temperatures are likely to intensify air pollution, notably ground-level ozone, which is a confirmed asthma inducer. Heatwaves also have the potential to aggravate respiratory diseases. Climate change can result in longer pollen seasons and higher pollen production, impacting people with allergic asthma. Alterations in rainfall patterns and higher humidity can foster the development of mould and dust mites, indoor allergens that induce asthma. Severe weather conditions such as wildfires, increasingly caused by global warming, emit particulate matter and smoke that can lead to asthma attacks.
Air pollution too, continues to remain a health emergency
While the impacts of climate change are now increasingly being felt, air pollution still remains a severe environmental and health emergency in India. The recent statistics from the World Air Quality Report 2024 indicate that India was the fifth most polluted nation in the world, with a mean PM2.5, more than ten times the World Health Organization safe threshold. Particulate pollution (PM2.5) is a significant issue. Between 1998 and 2021, the Indian average annual particulate pollution grew by 67.7%, lowering average life expectancy by roughly 2.3 years. An estimated 59.1% of the world’s growth in pollution between 2013 and 2021 originated from India.
Protecting vulnerable populations, especially children and the elderly, requires proactive strategies at both individual and societal levels. Ultimately, safeguarding the right to breathe clean air necessitates a concerted effort to mitigate climate change, implement stringent pollution control measures, and prioritise public health to prevent a future where respiratory distress becomes the norm.
(Dr. Amrish Patel, is a pulmonologist at Sterling Hospitals, Gurukul. Email: Drarpatel79@yahoo.co.in)
Published – May 07, 2025 03:17 pm IST
