Asthma and Air Pollution: Managing Symptoms in Indian Cities
Asthma is a chronic condition in which the airways are inflamed and over-reactive. They narrow in response to triggers, producing wheeze, cough, chest tightness and breathlessness. In much of urban India, one trigger is unavoidable and constant: the air itself.
How pollution interacts with asthma
Fine particulate matter (PM2.5) penetrates deep into the airways and causes inflammation directly. Ozone, nitrogen dioxide from traffic and sulphur dioxide from industry all increase airway reactivity. During winter months in northern India, when temperature inversion traps pollutants, emergency visits for asthma and COPD rise measurably.
Pollution does not only worsen existing asthma. Exposure in childhood is associated with a higher risk of developing it.
Recognising asthma
- Wheeze, especially on breathing out
- Cough that is worse at night or in the early morning
- Chest tightness
- Breathlessness on exertion or exposure to a trigger
- Symptoms that vary over time and improve with a reliever inhaler
Diagnosis is confirmed with spirometry showing reversible airflow obstruction, ideally before starting long-term treatment.
Common triggers besides pollution
- Dust mites, cockroach allergen, pet dander
- Pollen, particularly in spring
- Mould and damp
- Smoke from cigarettes, incense, mosquito coils and biomass cooking fuel
- Cold air, exercise
- Respiratory infections
- Strong perfumes and cleaning chemicals
- Aspirin and NSAIDs in a minority
- Gastro-oesophageal reflux
The two kinds of inhaler, and why the distinction matters
Reliever
A short-acting bronchodilator, usually salbutamol, opens the airway within minutes. It treats the symptom, not the underlying inflammation.
Controller
An inhaled corticosteroid, often combined with a long-acting bronchodilator, reduces the inflammation that drives the disease. It does not give immediate relief, which is exactly why people abandon it.
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This is the most consequential misunderstanding in asthma care. Relying on a reliever alone controls symptoms in the moment while inflammation continues, and it is associated with a higher risk of severe attacks and death. Major guidelines no longer recommend salbutamol-only treatment for adults and adolescents; everyone with asthma should be on some form of inhaled corticosteroid, even if symptoms are infrequent.
Needing a reliever more than twice a week is a signal that control is inadequate, not a sign that the reliever is working well.
Inhaler technique and the steroid question
Studies consistently find that a large proportion of patients use their inhaler incorrectly, which means the drug never reaches the airway. A spacer improves delivery substantially with a metered-dose inhaler and should be used routinely, not just for children.
Fear of steroids is widespread and largely misplaced here. Inhaled corticosteroid doses are a small fraction of oral steroid doses and act locally. The common side effects, oral thrush and hoarseness, are largely prevented by using a spacer and rinsing the mouth after each dose.
Reducing exposure in a polluted city
- Check the daily AQI and shift outdoor exercise to times when it is lower, usually late morning rather than early morning in winter
- Exercise indoors on high-pollution days rather than stopping exercise altogether
- A well-fitted N95 respirator reduces particulate exposure; a cloth or surgical mask does not
- A HEPA air purifier in the bedroom measurably reduces indoor PM2.5
- Keep windows closed during peak pollution hours and ventilate when air is cleaner
- Avoid indoor sources: incense, mosquito coils, smoking, unvented cooking
- Maintain a smoke-free home without exception
Managing an attack
Every person with asthma should have a written action plan. General principles:
- Take the reliever as prescribed and sit upright
- If there is no improvement, or if symptoms return within a few hours, seek medical help
- Never delay because you do not want to trouble anyone
When to seek emergency care
- Breathlessness that makes it difficult to speak in full sentences
- Reliever inhaler not working, or needed again within two to three hours
- Lips or fingertips turning blue
- Drowsiness, confusion or exhaustion
- A silent chest, where wheeze disappears while breathlessness worsens, which is a dangerous sign and not an improvement
This article is general health information. Asthma treatment must be individualised, and inhaled medication should not be stopped or changed without medical advice.