Across many Indian cities and urban regions around the world, rising temperatures are now making air pollution worse, creating a dangerous combination for people with asthma, Chronic Obstructive Pulmonary Disease (COPD), allergies and other respiratory conditions.

Doctors say heatwaves and smog together are placing growing pressure on the lungs, especially among children, elderly people and those already living with breathing problems. Medical experts increasingly describe the situation as a "double burden" because the body is forced to cope with both extreme heat and polluted air at the same time.

Research has shown that high temperatures can worsen air pollution, increase harmful ozone levels near the ground and trap dangerous particles in the atmosphere. For vulnerable individuals, this can trigger serious breathing complications and even hospitalisation.

Why hot weather makes pollution worse

During heatwaves, the atmosphere often becomes stagnant. Instead of pollutants dispersing naturally into the upper atmosphere, hot air remains trapped closer to the ground. This allows harmful pollutants to build up over cities for longer periods.

As temperatures rise, pollutants such as PM2.5, PM10, nitrogen dioxide and ozone begin accumulating in the air. Scientists say extreme heat also speeds up chemical reactions between vehicle emissions, industrial smoke and other pollutants, increasing the formation of ground-level ozone, which is one of the main components of smog.

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Ground-level ozone is particularly harmful because it directly irritates the airways and lungs.

In densely populated urban areas, the situation becomes even worse because of concrete buildings, traffic congestion and limited greenery. Experts refer to this as the "urban heat island effect", where cities retain heat for longer and pollutants remain trapped close to the surface.

Why breathing becomes harder during extreme heat

The human body already works harder during hot weather because it must constantly try to cool itself down. This increases physical stress, especially on the lungs and heart.

When polluted air is added to the mix, the respiratory system comes under even greater strain.

Doctors explain that hot, polluted air can irritate the airways, increase inflammation inside the lungs and tighten airway muscles. It can also make mucus thicker and stickier, reducing the body's ability to exchange oxygen efficiently.

As a result, people may develop coughing, wheezing, chest tightness and breathing difficulty.

For people with asthma or COPD, these changes can quickly lead to flare-ups and respiratory emergencies. Studies have shown that hospital admissions and respiratory-related deaths rise during periods of extreme heat combined with poor air quality.

Why asthma symptoms worsen during heatwaves

People with asthma are especially vulnerable because their airways are already sensitive and reactive.

Doctors say several common heatwave-related triggers can worsen asthma symptoms, including ground-level ozone, dust particles, smoke, pollen, vehicle pollution and high humidity levels.

Many asthma patients notice that they begin wheezing more frequently during hot weather. Breathlessness, chest tightness, persistent night-time coughing and increased inhaler use also become more common.

Children face particular risk because their lungs are still developing. They also breathe faster than adults, which increases their exposure to polluted air.

Why COPD patients face even greater danger

For people living with COPD, heatwaves can become especially dangerous.

COPD already damages the lungs and reduces their ability to handle environmental stress. During very hot weather, breathing itself becomes more demanding and oxygen levels may fall further.

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Doctors say rising temperatures can constrict airways, increase fatigue and worsen mucus buildup inside the lungs. Heat-related dehydration can make the mucus even thicker, making it harder for patients to breathe properly.

Research has linked prolonged heat exposure with higher COPD hospitalisation and mortality rates.

The effects of smog may continue even after the heatwave ends

One of the lesser-known dangers is that respiratory symptoms do not always disappear immediately once temperatures fall.

Experts warn that people may continue experiencing health effects several days after a heatwave or smog episode has passed.

Persistent cough, breathlessness, fatigue, disturbed sleep, increased sputum production and lower exercise tolerance can continue even after weather conditions improve.

Because symptoms may appear gradually or continue later, many people underestimate how seriously heat and polluted air can affect lung health.

Warning signs that should never be ignored

Doctors say immediate medical attention may be required if someone develops severe shortness of breath, chest pain or persistent wheezing during a heatwave.

Other serious warning signs include bluish lips or fingertips, confusion, difficulty speaking because of breathlessness, high fever accompanied by breathing difficulty, or sudden worsening of asthma or COPD symptoms.