India is facing one of the worst impacts of climate change – extreme heat. It’s no longer just a seasonal discomfort or a weather issue. It has become a serious health disaster that is silently growing and could soon affect every single person in the country. A new study shows that around 76% of India’s population is now at high or very high risk from extreme heat. The situation is alarming, but the actions taken to deal with it are very limited.

The study, titled “How Extreme Heat is Impacting India: Assessing District-level Heat Risk”, was released on May 20 by the Council on Energy, Environment and Water (CEEW). It was prepared by researchers Shravan Prabhu, Keerthana Anthikat Suresh, Srishti Mandal, Divyanshu Sharma, and Vishwas Chitale.

They created a Heat Risk Index (HRI) to understand how heat is affecting people across 734 districts in India. The index is based on 35 different factors, like how often very hot days and nights are happening, how many people live in a district, how many people have health issues or disabilities, and changes in land and buildings.

According to the study, people living in Delhi, Maharashtra, Goa, Kerala, Gujarat, Rajasthan, Tamil Nadu, Andhra Pradesh, Madhya Pradesh, and Uttar Pradesh face the highest danger from rising heat.

Heat risk is more than just high temperatures

Many people confuse heat risk with heatwaves or heat stress, but they are different things. The CEEW study clearly explains what heat risk really means.

  • A heatwave is a period of several days where temperatures are much higher than usual. But there is no fixed definition for it across the world.
  • Heat stress happens when the body temperature goes beyond 37 degrees Celsius. The body starts losing its ability to cool itself. If it reaches 40 degrees, it can cause heat stroke, which can be fatal.
  • Heat risk, on the other hand, is about how likely a person is to get sick or die because of extreme heat. This depends on:
    1. How intense the heat is (along with humidity)
    2. How exposed a person is to the heat
    3. What health conditions or other vulnerabilities they already have

The study points out that in many parts of India, very warm nights are increasing faster than very hot days. From 2012 to 2022, over 70% of Indian districts had five or more extra very warm nights per summer (March to June).

These warm nights are dangerous because they don’t let the body cool down after a hot day. This leads to problems like heat strokes and makes conditions like diabetes and high blood pressure worse.

Cities are heating up faster than ever – but are we ready?

Another major issue is the increase in relative humidity, especially in North India. Between 2012 and 2022, the Indo-Gangetic Plain saw a significant jump in humidity. Earlier, the region had 30–40% humidity, but now it’s up to 40–50%.

When humidity rises, it becomes harder for sweat to evaporate from the body, making it difficult to cool down. This makes heat stress more dangerous and increases the chances of heat-related illnesses.

The report also highlights urbanisation and population growth as key reasons behind rising heat risk. In big cities like Mumbai and Delhi, the high population density makes it hard to escape the heat. The same goes for rapidly growing cities like Pune, Thoothukudi, and Gurugram. These cities are filled with concrete buildings and roads that trap heat during the day and release it at night, making nights warmer.

In states like Andhra Pradesh, Maharashtra, Haryana, Punjab, Chhattisgarh, Bihar, and Uttar Pradesh, many people are already vulnerable due to poor health and poverty. These areas are likely to face the worst effects of extreme heat.

2024 – The hottest year ever

The year 2024 has been the warmest year on record, not just globally, but also for India. The global average temperature was over 1.5°C higher than the pre-industrial levels (1850–1900). In India, it was about 1.2°C higher than the average of 1901–1910.

Though India’s temperature rise is slightly lower than the world’s, the impact is already being felt. In 2024, the country experienced its longest and deadliest heatwave since 2010. There were over 44,000 heatstroke cases reported in India last year alone.

Heat is now killing people and causing serious health issues. But sadly, the systems in place to deal with it are not strong enough.

Heat Action Plans (HAPs) were created to help manage extreme heat. They are supposed to provide early warnings and prepare cities to protect people during heat events. However, a study by Sustainable Futures Collaborative (SFC) in March 2024 found that most of these plans are weak. Even cities that have these strategies are not implementing them properly.

The report warned that without proper planning and action, India will see more people die from heat in the future due to longer, stronger, and more frequent heatwaves.

What needs to change?

The message is clear: extreme heat is not just a future problem — it’s already here. And yet, most people are waiting for others to take action. The truth is, the damage has been caused by all of us — through pollution, cutting down forests, and ignoring the signs of climate change.

The heat disaster we are facing today is an invitation sent by us to nature. And nature is now replying with dangerous consequences. If we continue to ignore this, the results will only get worse.

What we need now is:

  • Better planning at local, state, and national levels.
  • Implementation of heat action plans, not just their creation.
  • Public awareness campaigns to help people understand how to protect themselves.
  • Urban development policies that include more green spaces, shade, and cooling systems.
  • Cleaner energy sources to reduce pollution and slow down global warming.

It’s time we stop blaming others and take responsibility. Because climate change and extreme heat are not waiting for anyone. The longer we delay, the higher the cost — in lives, in health, and in survival.

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