Climate change is often discussed through temperatures, rainfall and extreme weather. But its effects are also measured in sleep lost during hot nights, work disrupted by heat, respiratory strain from polluted air and changing conditions for infectious diseases. A new 2026 Lancet Countdown report highlights how these pressures are affecting India and why health protection must become part of climate planning.

Why climate is a health issue, not only an environmental issue

Heat affects the body’s ability to regulate temperature. During prolonged exposure, people may experience dehydration, heat exhaustion or life-threatening heatstroke. High temperatures can also worsen existing heart, kidney and respiratory conditions, affect sleep and reduce the ability to work safely outdoors.

The impact is not evenly distributed. Outdoor workers, older adults, infants, pregnant people, people with chronic illnesses and households without reliable cooling may face higher risks. People living in dense urban areas can also experience hotter conditions because buildings and roads retain heat.

Heat exposure can affect livelihoods and daily routines

The estimated 193 billion potential labour hours lost each year illustrates that heat is not only a medical concern. It affects agriculture, construction, transport, delivery work and other outdoor occupations. Lost working time can reduce income, disrupt services and place pressure on families already facing economic challenges.

Heat-health planning should therefore include safe work-rest schedules, access to drinking water and shade, early warning systems, cool public spaces and practical support for workers. Employers should not rely on workers to judge risk alone when conditions become dangerous.

Changing disease patterns need local attention

Climate and environmental conditions can influence where disease-carrying mosquitoes and other vectors thrive. Changes in temperature, rainfall and water storage may alter the suitability of some areas for dengue and malaria transmission. Flooding and disrupted sanitation can also increase exposure to waterborne pathogens. These relationships are complex: disease outbreaks depend on local ecology, housing, public health infrastructure, travel and prevention measures, not climate alone.

For households, basic precautions remain important: prevent stagnant water from collecting, use mosquito protection recommended by local health authorities, drink safe water and seek medical care for concerning symptoms. Do not self-diagnose dengue, malaria or other infections based only on online symptom lists.

Air pollution adds another layer of risk

Wildfire smoke, traffic emissions, industrial pollution and other sources of fine particles can affect the lungs and cardiovascular system. People with asthma, chronic lung disease, heart conditions, children and older adults may be more vulnerable. On days with poor air quality, check local official advisories and reduce strenuous outdoor activity when recommended.

Indoor air matters too. Smoke from cooking fuels, tobacco and poorly ventilated combustion sources can add to exposure. Where feasible, improve ventilation, avoid indoor smoking and use clean cooking options. Air purifiers may help in some indoor settings, but they do not replace emission reduction or public air-quality action.

Five practical ways to protect health

1. Plan around heat alerts

Check local weather and heat advisories. Reschedule strenuous outdoor activity to cooler hours where possible. Take breaks in shade or a cool space and follow workplace safety instructions.

2. Hydrate and recognise warning signs

Drink water regularly, especially during heat exposure, unless a clinician has advised fluid restriction. Heavy sweating, weakness, dizziness, headache and nausea can signal heat exhaustion. Confusion, collapse, seizures or very high body temperature may indicate heatstroke and require emergency care. Move the person to a cooler place and seek urgent medical help.

3. Reduce mosquito breeding sites

Empty, cover or regularly clean containers that collect water. Use screens, nets or repellents as recommended by public-health authorities. Community action matters because mosquitoes do not respect property boundaries.

4. Pay attention to air-quality guidance

When pollution levels are high, reduce prolonged or intense outdoor exertion if advised, particularly for children and people with existing health conditions. Follow local health advisories rather than relying on visibility or smell alone.

5. Protect vulnerable neighbours

Check on older relatives, people living alone, outdoor workers and anyone who may not have access to cooling or clean water. Community cooling centres, shaded public areas and clear emergency information can make a meaningful difference.

What cities, employers and health systems can do

Individual behaviour is only one part of the response. Cities can expand tree cover, shade, reflective surfaces and accessible cool spaces while improving drainage and water services. Health systems can use heat-health action plans, train frontline workers to recognise heat illness and strengthen surveillance for climate-sensitive diseases.

Employers can adapt shift timings, provide rest breaks and water, train supervisors and create clear stop-work procedures for extreme conditions. Schools can review outdoor sports schedules and ensure children have access to shade and drinking water. These measures work best when they are planned before a heatwave or outbreak, not improvised after people become ill.

Why climate-health data matters

Reports such as the Lancet Countdown bring together indicators on heat exposure, health impacts, energy, air pollution and policy. They help show where risks are rising and where action may be most useful. Estimates should be read with their definitions and methods in mind: potential labour hours lost are not the same as a direct count of individual illnesses, and national averages can hide large differences between states and communities.

Better local data can help authorities identify high-risk neighbourhoods, improve early warnings and direct resources to people who need them most. Climate resilience is also a health-equity issue because people with fewer resources often have fewer ways to avoid exposure.

Frequently asked questions

Sources

• The Indian Express — Climate change worsening heat stress and disease risks in India: Lancet report, October 2026.
• World Health Organization — Heat and health.
• World Health Organization — Air pollution and health.

General health information only. Follow local public-health advisories and seek professional medical care for symptoms or individual health concerns.