The sacred Hajj pilgrimage is one of Islam’s five pillars. It is a test of faith and endurance. The pilgrimage demonstrates unity among Muslims and their submission to Allah. It is a mandatory passage at least once in the lifetime for all Muslims who can physically and financially undertake it. This five-day pilgrimage traverses 6-21 kilometres daily. Activities include climbing Mount Arafat and enduring crowded conditions while performing rituals. In 2024, over 2 million attendees embarked on this sacred journey, out of which almost 1300 Hajj Pilgrims died due to heat and humidity.

The 2024 Tragedy: 1300 Hajj Pilgrims Died Due to Heat and Humidity

As per tradition, the annual Hajj pilgrimage commenced on June 14, 2024, drawing over 2 million pilgrims to Mecca, Saudi Arabia. Beginning on June 17–19, 2024, a severe heatwave gripped the region, peaking at a staggering 51°C (123.8°F). This fell under the Wet-bulb temperatures, which measure heat and humidity together, and reached a critical 29.5°C, surpassing thresholds deemed survivable for prolonged outdoor exposure.

On June 18, 2024, the deadliest day, with continuous high temperatures, limited shaded areas, and insufficient hydration, contributed to widespread heat exhaustion and fatalities, with estimates suggesting 1300 Hajj Pilgrims died due to heat and humidity.

This timeline shows pilgrims suffering prolonged exposure to extreme heat and humidity. For hours during rituals such as Tawaf (circling the Kaaba) and Sa’i (walking between Safa and Marwah hills), pilgrims were exposed to direct sunlight and intense heat. The high humidity made sweating ineffective, causing the body’s core temperature to rise dangerously, leading to heat exhaustion, heatstroke, and multi-organ failure, eventually causing the untimely event of 1300 Hajj pilgrims to die due to heat and humidity.

While official pilgrims had access to air-conditioned tents and water stations in Mina and Arafat, unauthorized pilgrims often lacked access to these facilities.

These unauthorized pilgrims could not access official aid, forcing many to endure the sweltering in poorly made makeshift shelters or open spaces. Unorganized bottlenecks in crowd movement during rituals further exacerbated the exposure, as pilgrims spent hours in tightly packed spaces with minimal ventilation.

The sheer volume of attendees led to overcrowding at key ritual sites, which stretched resources thin and made it difficult to provide timely medical assistance to those in distress.

Also Read: Unnatural Heatwave Hotspots Emerging Across The Globe Amid Rising Temperatures

Impact on Vulnerable Pilgrims and Response Efforts

Demographics of the victims who died due to heat and humidity were mainly older adults and those with pre-existing conditions. The majority of those afflicted on this journey were the old and chronically ill as their already worn down and weakened immunity made them more susceptible to the symptoms of prolonged exposure to extreme heat and dehydration, leading to rapid physiological deterioration.

International pilgrims worldwide were especially troubled by the arid and unfamiliar desert as they ventured from much cooler climates, such as Southeast Asia and Europe, where desert-like conditions are rare. Unaccustomed to such extreme heat, their limited knowledge of safe hydration and protective measures for intense heat further heightened their vulnerability.

Pilgrims who crossed borders without official permits, often traversing from nearby regions, constituted a substantial portion of the casualties. Due to their unofficial status, unauthorized pilgrims were excluded from many organized resources, such as cooling stations and air-conditioned accommodations.

Of course, Saudi authorities subsequently took emergency measures, including deploying water trucks, temporary cooling stations, and additional medical personnel to mitigate the impact. Still, the scale of the crisis overwhelmed these efforts.

Victims experienced symptoms including confusion, seizures, and unconsciousness before succumbing to organ failure due to heatstroke. Overcrowded local hospitals struggled to manage the influx of patients suffering from heat-related illnesses, further contributing to the high death toll.

Also Read: Urban Heat Islands: Mitigation Strategies For Cooler Cities

The Science Behind Heat and Humidity: Why It Turned Deadly?

The Wet Bulb Temperature (WBT) mimics the human body’s cooling process through sweat evaporation by measuring how hot it feels when humidity and air temperature are combined. It is calculated by wrapping a thermometer in a wet cloth and exposing it to airflow. When WBT rises, the body’s ability to cool through sweating diminishes.

Through millions of years of evolution, humans have gained much necessary to survive: the ability to regulate temperature through Sweat evaporation, the primary cooling mechanism. However, it requires dry air to work effectively. High humidity prevents Sweat from evaporating, trapping heat within the body.

Critical Wet-Bulb Temperature limits were crossed on this year’s Hajj pilgrimage route. A wet-bulb temperature of 35°C (95°F) is considered lethal, as the body can no longer dissipate heat, leading to overheating and organ failure within hours.

The threshold lowers for more vulnerable populations or those with admitted acclimatization to heat; the lethal threshold for the old drops to 32.5°C at 80% humidity. Vulnerabilities include reduced sweating efficiency, compromised cardiovascular systems, and decreased thirst responses.

Also Read: Walmart Misses Latest Emissions Reduction Goal: 3 Key Reasons Behind The Setback

Why Humid Heat is Deadlier than Just Heat?

The human body cools itself through sweating as it removes heat from the skin, and blood vessels near the skin dilate (vasodilation) to release heat.

In a humid environment, Sweat cannot evaporate as the air is already saturated with water vapor, reducing the sweat evaporation rate. Without sweat evaporation, the body accumulates heat, raising core temperatures to dangerous levels.

Heat storage expands when the combination of high humidity and heat is present, forcing the body to work harder and increasing strain on the cardiovascular system. As heart rate and blood pressure rise to maintain cooling, the risk of heart failure or stroke escalates.

In comparison, dry heat is much easier for our bodies to acclimate. Sweat evaporates quickly, allowing the body to cool effectively. In humid conditions, the lack of evaporation creates a “pressure cooker” effect, where internal temperatures climb uncontrollably and inconsistently.

Also Read: The European Union Emissions Trading System: Lessons Learned And Future Directions

Major Physiological Breakdown Under Humid Heat

Heatstroke

When core human body temperature surpasses 40°C (104°F), this increased core body temperature induces a state of confusion, loss of consciousness, and seizures. Left untreated, it results in multi-organ failure and eventually death.

Cardiovascular Collapse

As the heart pumps blood faster to dissipate the growing heart, prolonged strain leads to circulatory failure. Dehydration thickens the blood, increasing the risk of blood clots, heart attacks, and strokes.

Also Read: Linking Emission Trading Systems: Opportunities And Challenges In Global Carbon Markets

Local Climate Data: 2024 Hajj Conditions

During the 2024 Hajj, humidity averaged 33%, with peaks reaching 75%—a sharp contrast to historical averages of 25% during summer months in Mecca. The higher humidity magnified the effects of extreme temperatures, increasing the wet bulb temperature and reducing pilgrims ‘ ability to cope with heat.

The Heatwave was uncontrollable, as air temperatures during the Hajj soared to 51°C (123.8°F), the highest recorded for a pilgrimage season in recent memory. Combined with elevated humidity, conditions approached the upper tolerance limits for human survival, particularly for prolonged outdoor activities.

Environmental Factors

Saudi Arabia and the rest of the Arabian peninsula have witnessed a rise to an average temperature of 1.2°C, surpassing the global average of 1.1°C.

Globally, extreme heat and humidity events have doubled since 1979, driven by the accumulation of greenhouse gases in the atmosphere. This causes even more exasperated temperatures in areas that usually preserve a disproportionate level of sunlight, like Saudi Arabia, where summer temperatures frequently approach or exceed 50°C.

Future Projections

The Islamic calendar is lunar, causing the Hajj to shift approximately 10 days earlier each year. By 2049, the pilgrimage will again coincide with the hottest months of August and September. These months historically record average daily highs exceeding 45°C (113°F), with humidity levels likely to rise further due to changing climate patterns.

The emotional toll on the Muslim community was felt globally. Shock and mourning were widespread across the global Muslim community, bound by shared faith, felt the weight of the tragedy deeply. Mosques from Jakarta to London held special prayers for the victims. Social media became an outlet for collective grief, with hashtags like #Hajj2024Tragedy trending across platforms.

Also Read: Climate Change Drives Up Insurance Costs, And Missed Mortgage Payments

What Needs to Change: Mitigating Risks for Future Pilgrimages

Policy recommendations to expand access to cooling shelters are one major notice. The most present issue is the often limited capacity and accessibility of cooling shelters, which leaves many unauthorized or late-arrival pilgrims without refuge.

The proposed solution involves several new propositions:

• It will begin by building augmented-capacity shelters with strategically placed air conditioning near high-traffic areas like Mina, Arafat, and Muzdalifah. This would ensure that all pilgrims, including unauthorized ones, have access to these facilities without discrimination.
• Stricter heat safety protocols will be applied, and hydration stations will be installed every 500 meters in key areas, offering free electrolyte-enriched water to combat dehydration. Automated systems will also be used to monitor water levels and restock promptly.
• Construct shaded walkways for routes such as Sa’i and Jamaraat (stone-throwing ritual). Utilize the abundant desert sunlight for solar-powered cooling fans along these pathways.
• Introduce rest breaks during peak heat hours, enforced by crowd marshals, especially for older pilgrims.
• Develop multilingual awareness programs disseminated through Hajj apps, brochures, and pre-departure workshops, teaching pilgrims to recognize signs of heat exhaustion and dehydration.

This loss at Hajj is a wake-up call, if there ever was one. It is a solemn reminder of the need for change to honor the 1,300 lives lost.

It is yet another reason to commit to reducing carbon emissions and protecting vulnerable populations. Taking global responsibility appeals to policymakers, religious leaders, and citizens to take immediate action against climate change to safeguard this sacred pilgrimage.

Also Read: Impact Of Emission Trading On Developing Economies: Equity And Economic Growth