Sweating and sneezing: How October heat is fuelling a health crisis in India

As the monsoon clouds retreat, a different kind of discomfort settles over India. October, a time for crisp air and festivities, suddenly feels like an extension of summer’s wrath. In cities like Delhi, Kolkata, and Lucknow, people step outside only to be greeted by stifling heat.
What used to be a brief transitional period has stretched into something far more punishing — and the consequences are showing.
At first, it seemed like the usual seasonal flu: sniffles, mild fevers, and coughs circulating in families and among colleagues. But soon, what started as a harmless illness morphed into something more dangerous.
Hospital OPDs are reporting a surge in cases of dengue and malaria, with patients flooding in at alarming rates.
The culprit? It’s October heat. The month’s oppressive heat and humidity turns stagnant water into mosquito breeding grounds, pushing the immune system to its limits.
As global temperatures rise and weather patterns shift, the intensity of October heat is no longer just an uncomfortable phase — it’s becoming a serious health risk, one that India’s population is increasingly struggling to cope with.
October heat refers to the unreasonably high temperatures experienced in several parts of India during the month of October, following the withdrawal of the southwest monsoon.
During this time, the skies look clear, but humidity levels remain high, creating a perfect storm of discomfort. Temperatures in cities like Delhi, Mumbai and Kolkata often soar to 35–40°C, with little relief in the form of rain.
Nights offer little respite, as warm air lingers, trapping heat within buildings and making it difficult for residents to cool down.
This period is usually accompanied by dry winds and occasional hot spells that make conditions even more challenging. The monsoon’s departure leaves behind dampness in the air, which, combined with rising temperatures, creates a muggy and oppressive atmosphere, exacerbating the discomfort felt by millions across the country.
Historically, October heat has been an expected climatic event, but recent years have seen it becoming more intense, a worrying trend linked to climate change.
India’s October heat is becoming more than just an annual inconvenience — it’s a direct manifestation of the global climate crisis.
As the planet warms, the frequency and intensity of heatwaves are increasing, with India being particularly vulnerable due to its geography and dense population.
The rise in atmospheric greenhouse gases has led to higher overall temperatures, longer heatwaves, and more extreme weather patterns. In cities like Delhi, where air pollution is already a major issue, heatwaves amplify the environmental stress, making it harder to breathe and increasing the health risks for vulnerable populations.
Climate models suggest that as global temperatures rise, the October heat in India will only worsen.
The Intergovernmental Panel on Climate Change (IPCC) has warned that heatwaves will become more frequent and longer-lasting, pushing the limits of human endurance, especially in tropical countries like India.
As more heat is trapped in the atmosphere, it accelerates the warming of land surfaces, driving up daytime temperatures and leading to increased humidity.
The prolonged exposure to high temperatures and humidity during October heat can lead to a range of health problems, particularly among vulnerable populations, such as the elderly, children, and those with pre-existing health conditions.
The most immediate health threat during October heat is heat exhaustion and heatstroke.
Prolonged exposure to high temperatures, especially in urban areas where the urban heat island effect traps heat, can cause the body to overheat, leading to dehydration, fatigue, dizziness, and confusion. In severe cases, it can escalate to heatstroke, a potentially fatal condition where the body’s core temperature rises above 40°C.
“During this changing weather, there is a rise in the temperature and humidity, there is dryness in the air, lack of wind, causing uncomfortable, suffocating surroundings. This can at times be risky to our health. This sudden warmth can disrupt the immune system and create conditions favourable for the spread of certain viral and bacterial infections,” said Dr Pooja Khosla, Co-Chairperson, Department Of Medicine, Sir Ganga Ram Hospital.
The combination of high temperatures and humidity increases the risk of dehydration, especially for outdoor workers, such as farmers, construction workers, and street vendors, who cannot escape the heat. Dehydration can lead to kidney stress and, in extreme cases, kidney stones or acute kidney injury. The lack of adequate water intake, coupled with excessive sweating, places a significant burden on the body’s renal system.
October heat can also exacerbate respiratory problems. In urban areas, the combination of high temperatures and air pollution creates a toxic cocktail of pollutants. Ground-level ozone, formed when pollutants react in the heat, can trigger asthma attacks and worsen conditions like chronic bronchitis.
For the elderly and those with respiratory diseases, this period is particularly dangerous, as breathing becomes laboured, and emergency room visits for respiratory distress tend to spike.
“Hot and humid conditions are conducive to the growth and spread of certain pathogens, including viruses and bacteria. For example, waterborne diseases like typhoid and viral infections like the flu or common cold may become more common during this period,” Dr Tushar Tayal, Consultant, Internal Medicine, CK Birla Hospital told India Today Digital.
The combination of heat, high humidity, and poor air quality makes people more susceptible to respiratory infections. “Pollutants in the air can trigger or worsen conditions like asthma, bronchitis, and other chronic respiratory diseases,” Dr Tayal added.
The physical discomfort of prolonged heat exposure can have psychological effects as well.
Studies have shown that people living in consistently high temperatures experience higher levels of stress, irritability, and fatigue. The oppressive heat can lead to poor quality of sleep, impacting overall mental well-being.
In densely populated urban areas, where people live in small, cramped homes without adequate ventilation or cooling, the mental toll of October heat is even more pronounced.
For those dependent on agriculture, October heat can severely affect crop yields, especially for late-harvest crops. The stress of high temperatures, combined with the irregularity of rainfall, can lead to reduced productivity and crop damage.
For farmers already struggling with unpredictable weather patterns, the October heat adds to their burden. The resulting economic strain can lead to food insecurity and malnutrition, particularly in rural areas where people rely on their own crops for sustenance.
India’s response to the October heat is a mix of traditional practices, government initiatives, and community-led solutions.
In rural areas, people have long relied on techniques such as whitewashing houses, using mud huts, and constructing courtyards to cool their living spaces. These age-old practices remain effective in combating the harsh heat, particularly in regions where modern infrastructure is lacking.
In urban centres, however, the sheer density of the population makes it harder to escape the heat. The urban heat island effect worsens the situation by trapping heat in concrete and asphalt structures, leading to higher temperatures than in rural areas.
In cities like Ahmedabad, the local government has implemented heat action plans to mitigate the impact of extreme heat. These plans include early warning systems, public awareness campaigns, and the distribution of water and electrolytes in vulnerable areas.
While the October heat has been a part of India’s climatic pattern for decades, its increasing intensity demands a more coordinated and long-term response.
The government has made strides in recognising heatwaves as a public health hazard, but more needs to be done in terms of infrastructure development and urban planning to mitigate its effects.
Experts suggest that cities must invest in green spaces and cool roofs, as well as integrate climate-resilient building practices to combat the urban heat island effect.
“The challenges can be reduced by building disaster resilient infrastructure such as cool pavements with reflective coatings, adopting passive cooling technologies, creation of early warning systems for utilities in the power sector and improving operation procedures of critical infrastructure systems during extreme heat situations,” Amit Prothi, Director General, CDRI.
The rural population, which faces the brunt of agricultural and economic disruptions, would benefit from climate-resilient farming techniques and more effective water management systems to combat dehydration and crop loss.
With climate change amplifying the intensity of heatwaves, India must prepare to face longer, more frequent periods of extreme heat.
The country’s ability to adapt will depend on a concerted effort from both the government and local communities to find innovative solutions and ensure that its population remains resilient in the face of rising temperatures.