Why can't you stop coughing in Delhi, Mumbai right now? Is it pollution, flu or something else? Doctors explain

The cough surge reflects overlapping pressures rather than one clear cause. Delhi-NCR is already in the hazardous air-quality band, and Mumbai remains unhealthy. Winter has also begun, while clinics report sore throats, chest tightness, fatigue, and persistent coughs. Pollution, influenza, common colds, or combinations can produce similar respiratory symptoms.

A gradual dry cough with throat or eye irritation and no fever may follow polluted-air exposure. Influenza more often starts suddenly, with fever and body aches. Yet infection can begin without fever, and pollution can inflame airways already affected by a virus. A patient may therefore have several causes at once.

Doctors use timing, symptom progression, exposure history, and contact with sick people to narrow the cause. Symptoms that improve indoors or outside the city suggest an air-quality trigger. A new fever or coloured sputum after improvement can raise concern about a secondary bacterial infection. Medical review is important when warning signs appear.

AQI labels turn measured pollution into public-health warnings. “Unhealthy” generally means pollution can affect everyone, with greater risks for people who already have breathing or heart conditions. “Hazardous” indicates an even more dangerous pollution episode, where health effects may be widespread. These labels help people understand risk without reading separate pollutant measurements.

In the article, Delhi-NCR is already described as hazardous, while Mumbai is in the unhealthy band. Clinics in both metropolitan areas are crowded with people reporting persistent cough, sore throat, chest tightness, and fatigue. The article does not state the exact AQI readings, pollutant concentrations, or official thresholds behind either label.

The immediate concern is respiratory irritation and worsening airway inflammation. Pollution can also intensify symptoms during a viral infection. Because pollution may rise sharply after Diwali, people should take persistent or severe symptoms seriously. Breathlessness, chest pain, low oxygen saturation, or bloody sputum require medical advice.

The Air Quality Index, or AQI, summarizes pollution levels in a single number or category. Monitoring stations measure pollutants such as fine particles, larger particles, ozone, nitrogen dioxide, sulfur dioxide, and carbon monoxide. Each measurement is compared with health-based limits, and the pollutant creating the greatest risk usually determines the overall AQI category. Higher readings mean greater concern.

The article does not list the pollutants, AQI values, calculation method, or category thresholds for these cities. It reports that Delhi-NCR is in the hazardous band and Mumbai is in the unhealthy band. Those labels communicate that breathing conditions are concerning, especially for people with sensitive or already inflamed airways.

AQI is useful because it translates technical monitoring into practical risk information. It does not diagnose the cause of an individual cough. Doctors still need symptom timing, exposure history, medical history, and sometimes tests to distinguish pollution irritation from infection or a secondary problem.

The pattern over time is often more useful than the first scratchy throat. Pollution-related irritation tends to build gradually. It commonly causes dry cough, throat irritation, or irritated eyes without fever. Influenza usually begins suddenly and is more likely to cause fever and body aches. Colds and other viral infections may cause cough, sore throat, blocked nose, and breathing difficulty, so the distinction is not certain.

For example, symptoms that ease indoors or after leaving the city point toward an air-quality trigger. A person who develops sudden fever, body aches, or contact with sick people may be more likely to have an infection. However, Dr Sagar Srivastava noted that infections can begin without fever, making self-diagnosis difficult.

Doctors therefore ask when symptoms began, how long they have lasted, and how severe they are. They also ask about pollution exposure, sick contacts, asthma, and COPD. New fever or coloured sputum after improvement may indicate a secondary bacterial infection.

Pollution and viral infection can reinforce each other’s effects. Polluted air irritates and inflames the airway lining. A viral infection also inflames those passages and can make them unusually sensitive. When both occur together, symptoms may be stronger, last longer, and become harder to identify as environmental or infectious.

A patient might begin with a viral sore throat and cough, then continue coughing after the fever or infection resolves. Exposure to heavily polluted air can keep irritating the already sensitive airways. Dr Divya Gopal described this as pollution exacerbating existing airway inflammation during a viral infection. The patient may therefore have several causes at once.

This overlap complicates treatment and diagnosis. Doctors rely on symptom timing, severity, exposure history, sick contacts, and pre-existing asthma or COPD. Persistent symptoms need attention, especially with breathlessness, chest pain, reduced oxygen saturation, fever, or bloody sputum. A clinician can decide whether testing is needed.

A cough may outlast the infection because recovery of the airway lining is slower than disappearance of the virus. After a viral illness, the airways can remain inflamed and overly sensitive. Ordinary triggers, including polluted air, may then provoke coughing even when the original infection has resolved. Doctors call this post-viral airway hyperreactivity.

For example, someone may feel better after a viral infection but continue having a dry, nagging cough. Exposure to smog can irritate the still-sensitive airways and prolong the symptom. Dr Divya Gopal said this cough can last several weeks after the infection resolves. This does not automatically mean the infection is still active.

The duration and pattern still matter. Doctors assess severity, exposure, fever, sputum, and underlying conditions such as asthma or COPD. A fresh fever or coloured sputum after improvement may suggest a secondary bacterial infection. Breathlessness, chest pain, low oxygen saturation, or bloody sputum require medical advice.

Winter can worsen respiratory problems because colder, calmer air often disperses pollution less effectively, allowing irritants to remain concentrated near the ground. Cold, dry air can also irritate airways. These mechanisms are established environmental explanations; the article itself mainly reports that winter is setting in and air quality is deteriorating.

The timing around Diwali adds another pollution concern. The article reports hazardous air in Delhi-NCR and unhealthy air in Mumbai just days before Diwali. Weather experts believe pollution could spike sharply the day after Diwali. People already experiencing irritated or virus-affected airways may then develop more cough, throat irritation, chest tightness, or fatigue.

The result is a seasonal diagnostic challenge. Pollution, influenza, and common colds can look alike, while pollution can intensify a viral illness. Doctors will need to track symptom progression and exposure carefully. Warning signs such as breathlessness, chest pain, low oxygen saturation, or bloody sputum should prompt medical advice.