“On 22 May 2026, all 50 of the world’s hottest cities were located in India — a statistic without recent precedent in global weather records.”
On 22 May 2026, India dominated global temperature rankings in an unprecedented manner — 97 of the world’s 100 hottest cities were located within its borders, according to real-time data from the air quality and weather tracking platform AQI.in. Odisha’s Balangir topped the global chart at 48°C, followed by Sasaram (Bihar) at 48°C and Varanasi (Uttar Pradesh) at 47°C. The only non-Indian cities in the top 100 were three from Nepal: Dhangadhi (23rd), Nepalgunj (34th), and Lumbini Sanskritik (76th).
Other cities featuring in the global top 100 included Muzaffarnagar, Ayodhya, Patiala, Warangal, Haridwar, Sri Ganganagar, Gwalior, Dhanbad, Chandigarh, Bharatpur, and Singrauli — all recording between 45°C and 47°C. The 2026 heatwave reflects the compounding effects of climate change, El Niño, delayed pre-monsoon rainfall, and rapid urbanisation.
📜 IMD Classification and Alert System
The India Meteorological Department (IMD) — the national agency for weather forecasting and disaster meteorology — classifies heatwaves based on two parameters: absolute temperature thresholds and departure from normal seasonal temperatures.
- Heatwave (Plains): Minimum 40°C AND departure of ≥4°C to 5°C above normal
- Severe Heatwave: Departure ≥6°C OR absolute temperature ≥45°C
- Severe Heatwave (Absolute): Temperature ≥47°C qualifies on its own
- Hilly Regions: Threshold is 30°C
- Coastal Areas: Maximum temperature ≥37°C with departure ≥4.5°C
Green (no action) → Yellow (watch) → Orange (be prepared) → Red (take action immediately). Red alerts were active on 22 May 2026 across Delhi, Rajasthan, Punjab, Haryana, UP, MP, Vidarbha, Chhattisgarh, Bihar, and Telangana.
| Heatwave Type | Absolute Temp | Departure from Normal |
|---|---|---|
| Heatwave (Plains) | ≥40°C | ≥4°C to 5°C |
| Severe Heatwave | ≥45°C | ≥6°C |
| Severe Heatwave (Absolute) | ≥47°C | Any |
| Heatwave (Hilly Regions) | ≥30°C | ≥4°C to 5°C |
| Heatwave (Coastal) | ≥37°C | ≥4.5°C |
Think of IMD’s warning system like a traffic light — but with four levels instead of three. Green means all clear, yellow means stay alert, orange means get ready to act, and red means act now. On 22 May 2026, multiple states were on “Red” — the highest emergency level — simultaneously.
The IMD announced in mid-May 2026 that it is working to revise the existing heatwave criteria, as current parameters don’t adequately capture heat stress across all of India’s diverse geographical zones. A new percentile-based alert system — triggering warnings when temperatures exceed the historical 95th percentile for a given location — is under consideration. Why might a percentile approach be more equitable than fixed temperature thresholds?
🌍 Regional Spread and Temperature Records
The IMD forecast heatwave to severe heatwave conditions across large parts of northern and eastern India until at least 27 May 2026. States under the most severe impact included Uttar Pradesh, Odisha, Bihar, Chhattisgarh, Madhya Pradesh, Telangana, Haryana, and Maharashtra, with daytime temperatures running 4°C to 6°C above seasonal norms.
Western Odisha — particularly Balangir and Titlagarh — perennially ranks among India’s hottest zones in summer, but the 2026 intensity was described by meteorologists as exceptional. Banda (UP) had earlier in the week recorded 48°C, marking the highest temperature of the season at that point. The Vidarbha region in Maharashtra saw several cities cross 46°C. Meanwhile, Bhubaneswar on the coast recorded a dangerous early-morning Heat Index of 44°C owing to the combination of high temperature and extremely high humidity — illustrating that coastal heat stress operates differently from dry inland heat.
⚕️ Humidity, Heat Index and Health Impact
Across the worst-affected inland cities, relative humidity on 22 May 2026 was between 6 and 8 per cent. This low-humidity, high-temperature combination dramatically increases heat stress, accelerates dehydration, and raises the risk of heat exhaustion and heatstroke. Heatstroke — a medical emergency caused by the body’s failure to regulate core temperature — can lead to organ failure and death if not treated immediately.
Andhra Pradesh recorded 325 suspected heatstroke cases between 1 March and 19 May 2026. Hospitals across multiple states reported rising admissions for dehydration, diarrhoea, and heat exhaustion. Vulnerable groups — children, the elderly, outdoor labourers, and those with pre-existing conditions — face disproportionately higher risk.
Research published in Science of the Total Environment estimates that urban heatwaves increase daily mortality in India by nearly 15 per cent, generating over 1,100 excess deaths annually even in average years.
Don’t confuse Heat Index with Air Temperature. The Heat Index combines temperature AND humidity to reflect how hot it “feels” to the human body. Bhubaneswar’s early-morning Heat Index of 44°C was recorded even as air temperatures were lower than inland cities — because high coastal humidity amplifies perceived heat. This is why coastal advisories use a different IMD threshold (≥37°C, not ≥40°C).
⚡ Power Grid Under Stress
The 2026 heatwave placed extraordinary strain on India’s electricity infrastructure. On 25 April 2026, India’s peak power demand hit an all-time high of 256.11 gigawatts (GW), surpassing the previous record and running approximately 16 GW above projections. By 22 May, demand had climbed beyond 270 GW, prompting the government to appeal for conservation. India’s peak power deficit stood at approximately 2.57 GW on the evening of 22 May, according to grid regulator Grid-India.
The timing of peak demand is shifting structurally. Historically, India’s highest power demand arrived in June or July; the 2026 surge occurring in late April and May represents a weeks-long advancement driven by earlier onset of extreme temperatures. Nearly one-third of peak demand on 25 April was met by renewables, with solar contributing approximately 57 GW (roughly 22% of supply). However, battery storage limitations continue to constrain renewables’ ability to meet evening demand.
Battery storage limitations prevent solar energy from meeting peak evening demand — when people return home and switch on air conditioners, but the sun has set. This structural mismatch between renewable generation timing and peak consumption timing is one of India’s key energy transition challenges. How might grid-scale battery storage change the picture by 2030?
🏛️ Institutional and Government Response
Several state governments took administrative action to protect public health:
- Delhi: Announced summer school closure from 11 May to 30 June 2026 — a near-51-day break — and introduced a “water bell” system sounding every 45–60 minutes to prompt students to hydrate.
- Uttar Pradesh: Declared school holidays from 20 May to 15 June 2026.
- Odisha: Closed schools in late April 2026.
- Public health advisories across states recommended avoiding outdoor exposure between 11 AM and 4 PM, wearing light cotton clothing, carrying ORS (oral rehydration salts), and staying hydrated.
- Ministry of Labour reactivated directives for outdoor workers: drinking water, emergency ice packs, and frequent breaks.
Despite the severity of heatwaves, India does NOT classify them as natural disasters under the Disaster Management Act, 2005. This limits the formal flow of relief funds in the immediate aftermath of heat events — a major policy gap highlighted by the 2026 crisis.
🔬 Why 2026 Is Exceptionally Hot: Causes and Context
Climate scientists and the IMD have identified several converging factors behind the 2026 heatwave’s severity:
- Long-term Global Warming: Raising baseline summer temperatures, making heatwaves more frequent, intense, and longer-lasting
- Below-normal Pre-Monsoon Rainfall: Dry soil absorbs and radiates heat more rapidly, amplifying surface temperatures
- Urban Heat Island Effect: Concrete, asphalt, and reduced green cover trap heat and elevate nighttime temperatures
- El Niño Weather Pattern: If a strong or “super” El Niño develops later in 2026, it could make this one of the hottest years on record globally
The 2025 India–Pakistan heatwave (April–July 2025) recorded a peak of 48°C in Sri Ganganagar, Rajasthan, and claimed at least 455 lives in India. The 2026 event, arriving earlier and with broader geographic spread, has been characterised as more intense.
Economically, estimates cited by the Institute for Energy Economics and Financial Analysis (IEEFA) suggest extreme heat could cost India between 2.5 and 4.5 per cent of its GDP by 2030 through losses in labour productivity, agriculture, water availability, and healthcare expenditure.
🌐 Global Comparisons
While extreme heat is a challenge across South Asia — Nepal’s hottest cities also featured in the global top 100 on 22 May 2026 — India’s dominance of global temperature rankings on a single day is without recent precedent. The 2022 India–Pakistan heatwave and the 2023 Asia heatwave both registered isolated records, but neither produced a day on which a single country claimed 97 of the world’s 100 hottest cities simultaneously.
The World Meteorological Organisation (WMO) has previously warned that heatwaves are the deadliest form of extreme weather globally. South Asia is one of the most heat-vulnerable regions due to high population density, large outdoor labour forces, limited urban green space, and inadequate cooling infrastructure for lower-income populations.
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On 22 May 2026, India claimed 97 of the world’s top 100 hottest cities, with Balangir, Odisha at the top at 48°C, according to AQI.in data.
The IMD threshold for plains is a minimum of 40°C AND a departure of 4°C to 5°C above normal. For a severe heatwave, departure must be 6°C or more, OR temperature must be 45°C or higher.
India’s peak power demand hit an all-time record of 256.11 GW on 25 April 2026. By 22 May, demand had further climbed beyond 270 GW.
Heatwaves are NOT classified as natural disasters under the Disaster Management Act, 2005 — a key policy gap highlighted during the 2026 crisis that limits formal relief fund flows.
IEEFA estimates extreme heat could cost India between 2.5 and 4.5 per cent of its GDP by 2030 through losses in labour productivity, agriculture, water availability, and healthcare expenditure.
