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

Just days before Diwali, Delhi-NCR is already choking on “hazardous” air on Thursday, while Mumbai continues to be in the “unhealthy” band. Weather experts believe that there could be a sharp spike in pollution the day after Diwali.

With the Air Quality Index (AQI) deteriorating and winter setting in, India’s top metropolises are facing a sudden rise in cases of persistent, unyielding cough. Clinics are crowded with patients presenting with sore throats, chest tightness, and fatigue.

But a common question among the masses is: Is this cough a reaction to the toxic air, or is it a seasonal viral infection like the flu?

Medical experts told LiveMint that the confusion is entirely justified — The physiological responses to smog, seasonal influenza, and common colds look remarkably alike, making self-diagnosis tricky and complicating treatment.

Diagnostic dilemma: Why do they look the same?

The primary diagnostic challenge is that the respiratory system reacts similarly to both environmental irritants and viral invaders, the experts noted.

“At this time of year, the symptoms overlap considerably,” Dr Rommel Tickoo, Senior Director, Internal Medicine at Max Super Speciality Hospital, Saket, New Delhi, explained.

A patient presenting with persistent dry cough, fatigue and chest tightness could be “due to the polluted air, seasonal influenza, or a bacterial infection on top of irritated airways,” he said.

Dr Sagar Srivastava, Consultant Pulmonologist at Kailash Hospital in Greater Noida, agreed, noting that this mimicry makes clinical assessments difficult.

“The factors that lead to air pollution, the common cold, and the flu have some similar symptoms, including coughing, sore throat, blocked nose, and trouble breathing,” he said, adding that “this similarity makes it hard to identify the exact cause of the problem because while irritation from pollution does not include fever, infections can also begin without having a fever first.”

How to tell the difference?

While the initial scratchy throat might feel identical, doctors suggest patients look for specific patterns in how the symptoms evolve to narrow down the culprit.

The onset speed and the presence of systemic symptoms are key indicators.

“Influenza usually begins suddenly and comes with fever and body aches, whereas symptoms from pollution tend to build up gradually and are mostly irritation in the throat and eyes, without fever,” Dr Tickoo noted.

Environmental triggers, he said, also offer a major clue. “If a patient improves when they are indoors or when they travel out of the city, that points towards the air.”

Dr Tickoo explained that medical professionals also watch closely for secondary infections — “If someone was getting better and then develops a fresh fever with coloured sputum, we start considering a secondary bacterial infection.”

‘Double whammy’: When it is both

In many cases, the persistent cough isn’t an “either/or” situation, Dr Divya Gopal, Additional Director of Internal Medicine at Sir H.N. Reliance Foundation Hospital in Mumbai, noted.

The toxic air actually paves the way for viruses, and viruses leave the airways highly sensitive to pollution.

“Pollution can exacerbate existing inflammation of the airways in addition to the presence of viral infection in an individual, which means that a patient can have several causes of his/her condition,” Dr Gopal said.

This combination, she said, often leads to a prolonged, nagging cough long after the initial illness has passed. “There can be post-viral airway hyperreactivity, which leads to a cough lasting several weeks after the infection resolves.”

When to see a doctor? Why does it matter?

Physicians rely heavily on a detailed patient history to understand the primary cause of overlapping conditions.

“Symptoms, including when the first signs started, the duration of time and severity, along with other symptoms, will assist in narrowing down the cause,” said Dr Srivastava.

He said that doctors inquire about recent exposure to pollutants, contact with sick individuals, and pre-existing conditions like asthma or COPD. Then, depending on this history, doctors may order a complete blood count, CRP levels, viral panels (Influenza/COVID-19), or a chest X-ray to rule out pneumonia.

Therefore, Dr Gopal warned against dismissing severe symptoms as mere smog irritation.

“Do not jump to conclusions that persistent coughing is due to pollution,” she advised. “It is necessary to see a doctor if breathlessness, chest pain, fever, reduced oxygen saturation, or bloody sputum is present. Correct diagnosis will help prevent unnecessary use of antibiotics.”

Preventative measures

While individuals have limited control over the city’s air quality, doctors strongly recommend focusing on what they can control—specifically, getting vaccinated against the flu.

“While vaccination does not rule out influenza completely, it reduces the likelihood and helps us narrow down the cause,” Dr Tickoo said, urging older adults, pregnant women, young children, and those with comorbidities to get their shots. “It takes about two weeks to take effect, so it is better to get it now than to wait.”