Over the years, the city of Bengaluru has changed. As a practising clinician and pulmonologist, I have observed that the incidence and nature of airway problems in the city have changed, too. As we are morphing from a lush garden city to a concrete jungle, there is a loss of lung spaces and breathing corridors.
The historical accounts of the major lakes of Bengaluru are well known. Only a few of the nine-odd have survived. A recent visit to a residence in Benniganahalli and the Ramamurthy Nagar Welfare Association revealed that the residents de novo took up the task of reviving the Benniganahalli lake and crafting a wonderful breathing space with a walkway and greenery. So, changing for the better is possible too.
Recently, the government of Karnataka constituted an expert committee to analyse the effect of air quality index changes on healthcare under the National Programme on Climate Change and Human Health. The analysis, involving 1.25 lakh records, showed a high correlation between the incidence of acute respiratory infections and air-quality trends, with a strong seasonal pattern. The surge of infections heightened in the winter months (December-January) and a second surge was noted post-monsoon (August-September). A significant upward trajectory of about 77 percent was noted between 2023 and 2025.
However, respiratory infections’ relationship with AQI is complex. It appears that in most cases, AQI exceeding 100 acts as an amplifying factor. The volume of infections is often driven more by viral transmission dynamics. There is spatial distribution with biological mechanisms confined in urban Bengaluru, where high population density facilitates rapid transmission. Particulate matter of less than 2.5 and 10 micrometres in diameter induce oxidative stress and airway inflammation, impairing mucociliary clearance. All these factors lead to adverse health effects. Local epidemiological evidence coupled with time series analysis of hospital admissions demonstrate that daily fluctuations in PM 2.5 significantly increase hospital visits or admissions for asthma and respiratory emergencies.
The health effects of air pollution include increase in episodes of conjunctival irritation, upper airway symptoms, increase in allergic rhinitis, worsening asthma control, worsening symptoms of short-term chronic obstructive airway disease and long-term decline in lung functions. The non-respiratory effects include skin issues, cardiac impairments, increased clotting, metabolic changes and increase in strokes. The strongest evidence is in cardiac involvement, as documented in several studies.
A study evaluated over 1.36 lakh subjects between 2007 and 2013 for cardiovascular effects of long-term exposure to air pollution. This large study, whose subjects did not have prior cardiac issues, showed that PM 2.5 increased the risk of major cardiovascular diseases. The results stated that every 1 microgram per cubic metre increase in long-term exposure to fine particulate matter (PM 2.5 or smaller) is associated with a 36 percent increased risk of cardiovascular events.
While outdoor air pollution gets a lot of attention, indoor pollution hardly gets any. Apart from particulate matter, older buildings release higher amounts of Radon, with serious health implications especially for the elderly and homemakers, who tend to get exposed to the radioactive element more. When the building industry takes away breathing spaces, gardens and trees, it increases or amplifies both indoor and outdoor pollution.
What is the need of the hour? It is a proactive winter action plan with evidence-based interventions like monitoring indoor air quality, enforcing stringent dust control measures at construction sites, vaccination, revival of lakes, and constructing green corridors and public walkways. This includes system-level emission curbs in the transport industry that deals with fossil fuels, traffic curbs and improvement in mass transit, close attention to biomass burning, dust storms and temperature increase; and a facilitated migration to clean energy and carbon-capture mechanisms.
The effects of air pollution are not limited to asthma exacerbation alone or upper-airway issues. It is also closely linked to cardiac rhythm issues, premature mortality and general wellbeing of individuals. Therefore, there is a need for the public, the construction industry, non-government agencies, and regional and central government officials to join hands in making tangible and enduring changes to ensure cleaner air.
At the community and institutional levels, schools and workplaces in high-traffic areas need to be treated as priority zones. Better indoor ventilation and filtration, shifting outdoor assemblies or sports away from peak pollution hours, and creating low-exposure drop-off points for children are small, practical steps that reduce the dose of pollution without paralysing daily life.
Hospitals and clinics, meanwhile, should fast-track patients with viral flu-like illness and upper-airway symptoms. Ensure masking in crowded waiting rooms, especially during peak hours. Such measures will reduce the spread of infection. At the individual level, there are a few high-yield actions including vaccination, with an annual influenza shot before August-September arguably the single-most effective personal respiratory intervention. Others include timing outdoor activities by monitoring AQI, using proper N95 masks, and not ignoring the ‘minor’ symptoms and consulting a physician before things get exacerbated.
Dr Satyanarayana Mysore | Head of Pulmonology department, Manipal Hospital
(Views are personal)