Turning Up The Heat | Rising temperatures are reshaping Indian cities

If April and May are any indication, India is hurtling into a new era of extreme weather — one marked not just by blistering heat and sudden thunderstorms, but also by growing unpredictability.

This year, while some regions witnessed unseasonal rainfall, others battled early and prolonged heatwaves. The India Meteorological Department has warned of above-normal maximum temperatures across most of India in May. A recent study by the Council on Energy, Environment and Water finds that 57% of India’s districts — home to three-fourths of the population — now face ‘high’ to ‘very high’ heat risk.

Urban India is at the epicentre of this crisis. While one part of a city is lashed by sudden storms, another scorches under 40°C-plus conditions — with urban heat islands making some pockets even hotter. These extremes highlight the need for ward-level heat risk assessments and localised action plans. Heat stress is no longer a seasonal inconvenience — it's a public health, infrastructure, and governance challenge.

It doesn’t come alone. With rising temperatures, cities are also staring at deepening water stress. Bengaluru, Pune, Chennai, and Delhi have all grappled with water shortages in recent years. Heatwaves intensify this crisis — they don’t just dry up sources, they dramatically drive-up demand as well. Without urgent, hyperlocal action to build heat resilience, India’s urban centres will remain on the frontline of the climate crisis.

Hot cities, increasing water demand

High temperatures increase evaporation from surface water bodies, thus reducing water availability. They increase the overall water usage for domestic uses, including for cooling and personal hygiene. The drinking water needs in tropical and hot climates in comparison to temperate and cold climates is about two times more — 4.5 litres against 2.6 litres per capita per day. This is worth considering for future water resource planning.

Also, high temperatures can adversely impact the water quality — warm water can lead to algal blooms and reduce dissolved oxygen. Low water inflow conditions during summers accentuates the pollution in the local water bodies and rivers passing through our urban centres. The stretch of River Yamuna in Delhi is a good example.

Strengthening water management with a focus on resilience is vital as three parallel realities highlight the challenges our cities are facing. First, India’s overall water demand is predicted to increase by 32% by 2050. Second, heatwaves are the new normal, and are here to stay and get prolonged in the near future. Finally, around 40% of India’s population is expected to live in urban areas in the next five years.

Mapping water risks

First, mainstream heat risk assessments for water systems in Indian cities.

Given the differential impact of a heatwave, municipalities must prioritise conducting ward-level heat risk assessments for water systems that include monitoring the supply-demand dynamics of drinking water before the summer season begins. This will also involve the demarcation of vulnerable populations, such as senior citizens and children, and vulnerable areas, such as slums, that may face heightened impacts of heatwaves and water crisis at the ward level. Such segregated assessments are hardly undertaken by cities.

In addition, monitoring seasonal changes in the supply and demand of water, including its quality, will help predict the periods of severe water scarcity, and plan better to address this challenge. Currently, various agencies in the city monitor and analyse water quantity and quality data in isolation, leading to the lack of a holistic understanding of where to act.

Second, reduce water losses and increase the usage of treated used-water.

An increasing number of cities — Delhi, Bengaluru, Jaipur, or Hyderabad — get water for domestic uses from distant sources. During summers when the temperatures are high, and no freshwater addition takes place in most of the rivers or lakes, the supply from distant sources becomes unreliable. Hence, the increased water demand during summers, especially when heatwaves strike, becomes difficult to meet.

In the medium to long term, cities should adopt measures to plug water losses from distribution systems, such as by installing bulk flow water meters to identify leakages. Alternate sources of water, such as treated used-water, should be promoted for non-potable purposes such as landscaping, road cleaning, and construction, to free up the pressure on freshwater.

Policies do exist to support them. Delhi and Bengaluru are installing bulk water flow meters in their water distribution systems. More than 10 Indian states have a used-water reuse policy. These must be scaled up through proper planning for both water loss reduction and reuse. Thane’s reuse plan establishes reuse avenues and critical quality standards for the reuse of treated water.

Third, enable financing for strengthening water-related infrastructure and generating sufficient revenues to cover the operation and maintenance cost of water services. Specifically, for water supply infrastructure, municipal bonds like those floated by Indore and Ahmedabad municipal corporations are interesting financing instruments. Similarly, public-private partnerships on the lines of the Hybrid Annuity Model followed by the National Mission on Clean Ganga for strengthening used-water treatment infrastructure in states sharing the Ganga basin is a good example.

With nearly half of India’s population predicted to live in cities by 2050, we must ensure that heat stress doesn’t halt access to basic water services. Cities will continue to grow, but we must acknowledge climate change as a reality and undertake hyperlocal planning to tide over the heat and let the water flow.

(Nitin Bassi and Vishwas Chitale are senior programme leads with the Council on Energy, Environment and Water. Views are personal.)

Disclaimer: The views expressed above are the authors' own. They do not necessarily reflect the views of DH.