[India is once again in the grip of deadly heatwaves—and once again, it is the poor who suffer the most. As temperatures climb past survivable thresholds, the country’s vast informal workforce continues to toil under an unforgiving sun. They do so without access to protective gear, safe drinking water, rest breaks, or even shade. From blistering heat waves and flash floods to unsafe housing and precarious livelihoods, the working class is on the receiving end of this escalating crisis.

While news coverage often focuses on IMD forecasts and record-breaking temperatures, the deeper crisis unfolds on the margins, where workers face the collapse of their health, income, and dignity with little institutional support. Climate change, as climate and energy researcher Soumya Dutta reminds us in this article, is not a distant threat. It is here, and it is devastating.

A recent report by Down to Earth reveals that official figures vastly understate the toll of heatwaves on the toiling population. These figures fail to account for deaths indirectly triggered by extreme heat—such as cardiac arrests or kidney failure among already vulnerable groups. This erasure weakens public urgency and limits necessary policy action, further deepening the crisis for those most at risk. – Ed.]

Climate Change crisis has become one of the biggest challenges facing humanity, and there is no ‘relief’ in sight as mitigation actions (sharply reducing the emission of greenhouse gases) by almost all governments and businesses are way short of those required, sharply increasing the threat levels on all vulnerable communities across the world. With the weak climate pledges from governments, the world is set for about 2.9 °C average temperature rise by the end of the century. And the march of ‘hottest years on record’ are converging more on all the recent years, with 2023 and 2024 breaking the hottest year records. The year 2024 was about 1.58 °C warmer than the pre-industrial average temperature (average of those between 1850-1900). Sadly, facing an advancing climate catastrophe, the global GHG emissions have kept rising even after the over hyped Paris Climate Change Agreement (PA) of 2015.

Out of the approximately 146 crore (1.46 billion) people who inhabit India today, a major proportion belong to the poor working class who are forced to engage in physical labour to earn a basic living, even in extreme weather and climatic conditions. These include construction workers, street vendors, farm labourers, porters, rickshaw drivers, small scale fish-workers, Gig workers, domestic helps, sanitation workers, and so on. And these are the people worst affected by the increasing impacts of extreme climates, with the least resources to cope with the impacts. One of the fastest rising climate change impacts is the rise of heat-waves and heat index (simultaneous rise of air-temperature and relative humidity).

Heat waves and Heat Index

Over the past several years, heatwaves (and the less publicized but more lethal - heat index¹, which is a deadly combination of high temperature and high humidity) have adversely affected and even killed an increasing number of people across the Gangetic basin, north-west India and parts of the peninsular India. There has been some research on this, and several international publications have highlighted the extreme seriousness of the threats. One of the well researched papers on the increase in heat-wave days and mortality due to heat-waves (including heat index) published in the journal Science Advances² analyzed changes in summer temperatures, the frequency, severity, and duration of heat waves, and heat-related mortality in India between 1960 and 2009 using data from the India Meteorological Department. The study warns that even slight increases in average temperatures significantly raise the risk of heat-related deaths, especially in densely populated and economically vulnerable regions.

It is to be noted that some of the worst affected regions are also those where the population densities are relatively higher with a larger working class population. Today we have a world where over 56% of the global population lives in cities, and a significant part of these people in cities of the developing countries belong to the poor. Out of a number of climate change impacts, urban poor are impacted most by sharply increasing heat waves, dangerous heat index and urban flooding incidents. And when the average temperatures become high, urban areas suffer from even higher temperatures, not least because of the Urban Heat-Island Effect, which keeps city temperatures about 4 to 6°C higher than surrounding open areas.

The Urban Heat Island Effect occurs because of heavy use of steel, concrete, glass etc in cities and the black-top and concrete roads – all of which traps the heat and stores it for longer periods. By some estimates, in the year 2023, about 550 million or roughly 37-38% of the Indian population are living in cities. All these 550 million, poor or rich are exposed to sharply increasing climate change impacts (recent devastating Bangalore floods being just one example), but the poor and working class are far more exposed and have much less wherewithal to cope.

The global temperature rise is also causing more heavy downpours and flooding events, along with more heat-waves. It was found by some extreme event attribution studies that the 2022 extreme heat wave incidents in India and Pakistan were made 30 times more likely due to climate change, and these happened during a La Nina year, supposed to be cooler than normal.

In India, it is the IMD who determines and announces if and when a heatwave condition has started in any place and time by the Maximum temperature recorded - for the Plains 40°C, for Coastal areas 37°C and for Hills 30°C, with these conditions prevail for at least 2 days, with recorded temperature 4.5°C above ‘normal’ for the time. Severe heat waves occur when the departure from normal is significantly higher (5-6°C or 7°C or more, depending on the normal maximum temperature), or if the actual maximum temperature reaches 45°C or more.

A recent (2020) comprehensive assessment of climate change impacts and trends over the Indian region, by India’s Ministry of Earth Sciences, shows a frightening scenario projection in terms of both extreme precipitation and extreme heat incidents, as we go past the coming decades. On top of these, coastal cities and towns are now facing more frequent and more intense tropical storms and cyclones, driven by higher sea surface temperatures in both the Bay of Bengal and the Arabian Sea and these trends will worsen.

There is ample empirical evidence of these increases in India, as the graph here shows the sharply rising surface temperatures over the 50 year period from 1965 to 2015. The urban heat island effects are also increasing due to increasing construction density and decreasing open green spaces. Again, the working class are packed in cramped unsafe housing and forced to work exposed to the elements.

Impacts on Working Class

As mentioned briefly, the three climate impacts that are directly and increasingly impacting poor working class people the most, more in urban India but also the rural poor workers, in both their workspaces and their unsafe residential areas, are longer and more severe heat waves, rising heat index, sudden heavy rainfalls and flooding (accompanied with landslides in hilly areas).

According to the World Health Organisation (WHO), population exposure to heat is increasing due to climate change, with extreme temperature events becoming more frequent, longer, and intense. While rising global temperatures affect everyone, certain populations, such as the elderly, children, pregnant women, outdoor workers, athletes, and the poor, are more vulnerable to heat-related health risks. Gender also plays a role in heat exposure.

The human body cannot easily tolerate ambient conditions exceeding 37°C. At temperatures of 37°C and a relative humidity exceeding 40%, healthy individuals may begin to experience heat stress with prolonged activity or exposure, which most physical workers are forced to do as their only means of livelihood. Heat stress causes fatigue, headache and muscle cramps, while heat stroke can lead to death, even among healthy people. Those with chronic health conditions like diabetes or high blood pressure, heart and kidney conditions etc are at greater risk of suffering heat stress and heat stroke.

Data and Advisories are Not Enough

Manual workers have to spend a large part of their often long working hours in some of the hottest regions of an urban area (black-top streets and concretised pavements are often much hotter than the temperature records given by the meteorological department as these records are 2-meter air temperatures, not the hotter surface temperatures). Thus they are exposed to a greater degree to the impacts of heat waves and heat index. After a long day of tiring work in hot surroundings, they are often denied a chance to cool off and recoup at home, as the tightly packed and poorly ventilated houses many of them live in also become centres of heat and humidity build up.

Thus, in many places in a city where people are doing manual/physical work, they face heat stress and severe heat-wave like conditions due to Urban Heat Island effect, even if the official data has not recorded heat-wave conditions. Heat and humidity build-up is another serious risk factor.

Unfortunately, many of the Heat Action Plans prepared by State governments and Urban Local Bodies do not take into cognisance these factors. There is no clear mechanism to monitor at micro-spatial scales where these workers are located, many recording stations being located at spacious shaded areas. These preclude early detection and preventive measures. Neither is the met department able or willing to declare a “heat wave” if a zone in the city with heavy concentration of exposed outdoor workers exceeds dangerous temperatures or humidity levels.

The advisories that the government issues when IMD announces a heat-wave condition is inadequate to deal with the problems. One, advisory regarding avoiding outdoor work, especially for several days places the workers in severe economic stress. They should be compensated for the loss of working days, as these people are in no way responsible for creating global heating and climate change, while suffering the most from its impacts. Second, if it is a high temperature and humidity condition, the advice of “drink plenty of water” will not help cool the body enough, as evaporative cooling from the skin surface will be very low. These conditions put a lot of stress on both the heart and kidneys. If high temperature and high relative humidity conditions severely affect someone, external cooling of the person is needed to save that person.

Similarly, during urban flooding incidents, it’s the streets which become water carriers and submerged, in the absence of adequate storm drainage in most Indian towns and cities. Most of the rain water is channelized to the streets and they often become mini rivers, damaging any unsecured belongings over them. On top of that, the housing areas of urban poor are often located near the drainage channels of cities, and the flood waters regularly damage their weakly built dwellings. As the IMD studies have shown, climate change has already changed the monsoon rainfall patterns, with fewer but more intense rainfall days, interspersed with long dry periods. This is again a cause for more severe urban flooding and increased fires.

A fourth climate change impact is increasing in recent years, and that is the rising cases of urban (also forest) fire incidents, as many of the ‘informal’ settlements are littered with flammable materials, and the hot and dry periods make conditions ideal for both accidental or other fires.

Need for Action

• Local Monitoring: Implement local temperature and humidity monitoring in working areas, especially for street vendors, using simple and affordable instruments.
• Dialogue and Awareness: Employers and the government must engage with unions and workers’ organizations to raise awareness about heat-related health risks and the science behind them.
• Compensation for Lost Work: There should be provisions to compensate workers for lost working days due to heatwaves and similar climatic events.
• Emergency Cooling Rooms (ECRs): Establish ECRs in heavily populated working areas (e.g., markets, railway stations) to help prevent heat stress and heatstroke. This must be expanded to all working-class work areas.
• Heatwave as a Notified Disaster: Push for the government to declare heatwaves as a notified disaster to trigger automatic remedial actions.
• Urban Flooding: Improve localized weather monitoring, early warning systems, and action plans to address urban flooding effectively.
• Elevation Mapping and Drainage: Focus on mapping flood-prone areas and enhancing storm drainage capacities to reduce flood damage.
• Urban Fire Prevention: Monitor local temperatures and humidity for early fire warnings; prepare communities and review fire department equipment to respond effectively in vulnerable and narrow lane areas.

All or most of these will require not only responsive governance, informed policies and action plans, but crucially – local level capacity building of the vulnerable communities too.

1. Also known as “feels-like” temperature. High humidity hampers sweat evaporation, making even moderate temperatures dangerously unhealthy by sharply increasing the risk of heat-related illnesses.

2. “Increasing Probability of Mortality During Indian Heat Waves” ” Published in Science Advances, VOL. 3, NO. 6