Climate Change

Heatwaves arrive early in 2023; hit 11 states from March 3 to April 18

22 states/UTs recorded above-normal maximum temperature on April 18, 2023

By Kiran Pandey
Published: Thursday 20 April 2023
A heat wave is declared when the maximum temperature of a station reaches at least 40 degrees Celsius in the plains, at least 37 degrees Celsius in coastal areas and at least 30 degrees Celsius in hilly regions and the departure from normal is at least 4.5 degrees. Photo: iStock

The impact of climate change and global warming have shown up early this year. Large parts of the country have reported temperatures higher than average and heatwaves began as early as March 3 this time. 

Over 60 per cent of India or 22 states and Union Territories recorded above-normal maximum temperature on April 18, 2023, according to All India Weather Summary and Forecast bulletin by India Meteorological Department released April 19, 2023.

Read more: India underestimating heatwave impact, more than 90% of the country at risk: Study

India also witnessed a 34 per cent rise in deaths due to heat waves between 2003-2012 and 2013-2022, according to IMD data. 

The data on heatwaves can also be viewed on India’s Atlas on Weather Disasters by New Delhi-based non-profit Centre for Science and Environment and Down To Earth

Through March 2023, three states recorded heatwaves, according to data by IMD. The number went up further — 11 states and UTs recorded heatwaves from March 3-April 18, 2023. 

Heatwaves in India have been making headlines this week — 13 people reportedly died from heatstroke on April 16.

On April 20, a University of Cambridge study reported that 90 per cent of the country was at risk of suffering losses in livelihood capacity, food grains yields, vector-borne disease spread and urban sustainability due to heat. 

A heatwave is declared when the maximum temperature of a station reaches at least 40 degrees Celsius in the plains, at least 37 degrees Celsius in coastal areas and at least 30 degrees Celsius in hilly regions and the departure from normal is at least 4.5 degrees

Maximum temperatures in India on April 18, 2023

Source: IMD 

The year’s first heat wave was recorded in Karnataka on March 3. Till March 9, the state had recorded four heatwave days. Goa followed with four heatwave days and Gujarat with two. The last heat wave of the month was recorded on March 12, 2023.

There was a month’s respite before the next heatwave began in the country on April 12, 2023 in the Gangetic West Bengal. Andhra Pradesh, Bihar, Chandigarh, Haryana, Odisha, Puducherry, Punjab and West Bengal recorded heatwaves from April 12-18. 

The current situation calls for preparedness, especially because heatwave conditions will likely continue and affect human health too. 

Read more: Bats dying of heat stroke: Experts fear mass population collapse, zoonotic diseases

IMD has issued alerts in at least eight states on heatwave or heatwave-like conditions up to April 21, 2023. These extreme conditions are forecast to continue in Bihar, West Bengal, Odisha and north Coastal Andhra Pradesh up to April 26, 2023.

There is enough evidence to establish the impact of heatwaves on human health. Such extreme events attributed to climate change are fatal, too and call for adequate preparedness.

For instance, March 2022 — the warmest March on record — claimed 30 human lives in the country. The unusual, early heatwaves sweeping India and Pakistan in 2022 were made 30 times more likely due to the direct impact of climate change, according to the study by World Weather Attribution Network.

Deaths due to heatwaves in India


Number of deaths









































Source: IMD  

In India, 5,541 people died from heatwaves between 2013 and 2022. In comparison, 4,134 deaths were recorded due to heatwaves between 2003 and 2012. However, the number of deaths due to heat waves have decreased since 2020.

Heatwaves are now arriving earlier in the year, indicate the recent trends in 2022 and 2023. The first heatwave in 2022 was recorded on March 11, 2022 in Gujarat. The IMD said heatwaves had arrived earlier that year. 

Heatwaves 10 days earlier this time compared to 2022. It may be noted that Karnataka had not recorded heat waves in the last two years (2021 and 2022). 

Government in action

Acknowledging the impact of heat wave, the Union Ministry of Labour and Employment on April 18, 2023 asked all states and UTs to ensure preparedness and effective management of the impact of ensuing heatwave conditions on workers and labourers working in different sectors

In a letter to all states, the Centre has asked them to reschedule working hours for workers and labourers across different sectors, according to a PIB release

Read more: Most heat action plans in India are not suited to local contexts: Study

The states were asked to issue directives to the occupier, employers, construction companies and industries to undertake necessary steps to mitigate the adverse effects of scorching weather

Eighteen states in the country have prepared the heat illness action plan for response at state level, the Union Ministry of Health and Family Welfare told Rajya Sabha on March 21, 2023. 

The state-level plans are based on the national action plan (NAP) on heat-related illness released by the health ministry in 2021. The NAP guides how to manage severe heat-related illnesses, including clinical management, health facility preparedness and surveillance.

So, while the government issued the advisory, the states are expected to work according to their respective heat action plans to address the health impacts of heatwaves.

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