Hong Kong CNN  — 

Heavy showers blanketed northern India over the weekend, offering some much needed respite from a blistering heatwave that ravaged the region. But with mercury levels expected to remain high in other areas, the soaring heat has highlighted how millions in the world’s most populous nation are among the most vulnerable to the effects of the climate crisis.

The weekend downpour in Uttar Pradesh was a welcome change for the northern state of 220 million after temperatures in some areas soared to 47 degrees Celsius (116 Fahrenheit) last week, sickening hundreds with heat-related illnesses.

On Sunday, temperatures dropped acutely in Lucknow to around 32 degrees Celsius (87 Fahrenheit), as the capital, along with other cities, experienced the first rain during this year’s monsoon season. Video broadcast on local television showed people getting soaked in the rain and commuters navigating waterlogged roads.

Sunil Ghosh/Hindustan Times/Shutterstock
Commuters out in the light rain on the Sector 21 road, on June 25, 2023 in Noida, India.

The rain in Uttar Pradesh is likely to continue this week, bringing cooler temperatures to the region. But in the neighboring state of Bihar, unrelenting heat has extended into its second week, forcing schools to shutter until Wednesday.

At least 44 people have died from heat-related illness across the state in recent weeks, a senior health official told CNN, but the number could be much higher as authorities struggle to accurately assess how many people have died from heatstroke.

Temperatures are expected to slightly cool over the coming days, according to the Indian Meteorological Department (IMD), however experts say the climate crisis is only going to cause more frequent and longer heatwaves in the future, testing India’s ability to adapt.

Sunil Ghosh/Hindustan Times/Shutterstock
Commuters pass through a heavily waterlogged stretch of road on June 25, 2023.

“India has a history of dealing with heat… There are going to be millions affected,” said Dr. Chandni Singh, Senior Researcher at the Indian Institute for Human Settlements, adding the number of deaths that will be result from staggering heat depends on how prepared health systems are to deal with it.

“If health systems aren’t functioning, when you don’t have adequate emergency services, it will lead to (more deaths),” she said. “But what we know for certain is we are going to be approaching limits to survivability by mid-century.”

India is not the only country in the region to experience such sweltering heat in recent weeks.

Temperatures in northeast China are expected to remain high in the coming days, with mercury levels rising above 40 degrees Celsius (104 Fahrenheit) in certain cities, according to its meteorological observatory.

In Pakistan’s capital Islamabad, temperatures soared to 39 degrees Celsius (102 Fahrenheit) last week before weekend rain brought some relief to the region.

And studies warn the impact of extreme heat could be devastating.

Prolonged heat

India often experiences heatwaves during the summer months of May and June, but in recent years, they have arrived earlier and become more prolonged.

Last April, India experienced a heatwave which saw temperatures in capital New Delhi go beyond 40 degrees Celsius (104 Fahrenheit) for seven consecutive days. In some states, the heat closed schools, damaged crops and put pressure on energy supplies, as officials warned residents to remain indoors and keep hydrated.

India is among the countries expected to be worst affected by the climate crisis, according to the Intergovernmental Panel on Climate Change (IPCC), potentially affecting 1.4 billion people nationwide.

And experts say the the cascading effects of this will be devastating.

A study published in April by the University of Cambridge said heatwaves in India are putting “unprecedented burdens” on India’s agriculture, economy and public health systems, stalling efforts to reach its development goals.

“Long-term projections indicate that Indian heatwaves could cross the survivability limit for a healthy human resting in the shade by 2050,” the study said. “They will impact the labor productivity, economic growth, and quality of life of around 310 - 480 million people. Estimates show a 15% decrease in outdoor working capacity during daylight hours due to extreme heat by 2050.”

Singh said India has already taken steps to mitigate the impacts of high temperatures, including altering working hours for some outdoor workers and increasing heat education.

But the effects of extreme heat will impact our environment, energy consumption and eco-systems, she warned.

“Typically in a heatwave, you also see related water scarcity and droughts. You see the failure of the electricity grid. These risks start stressing the entire system,” she said. “Crop productivity will get affected. There will be huge impacts on other animals. When we come up with heat reduction plans, these are all things that are important to remember.”

Extremes of weather

India’s heatwave in the north came as heavy rain battered the country’s northeast, with pre-monsoon rain in Assam state triggering landslides and heavy flooding.

Nearly half a million people have been affected after heavy showers battered the region, turning roads into rivers and submerging entire villages. The rain in Assam came one week after after tropical cyclone Biparjoy hit India’s west coast, ripping trees and toppling electricity poles.

Elsewhere in the region, Pakistan also saw heavy rain in capital Islamabad over the weekend, bringing some relief from the high temperatures the week prior.

The rain may cause urban flooding in key cities, the country’s weather forecasting center said, advising farmers to manage their crops and encouraging travelers to remain cautious.

Kevin Frayer/Getty Images
A woman cools herself on a misting fan as she waits for a table outside a popular local restaurant during a heatwave on June 23, 2023 in Beijing, China.

China is expected to see soaring temperatures across several cities, including capital Beijing.

Last week, Beijing’s temperature soared above 41 degrees Celsius (105.8 degrees Fahrenheit), setting a new record for the capital’s hottest day in June.

According to the country’s meteorological observatory, Beijing, Tianjin, Heibei, Shandong will “continue to be baked by high temperatures.”

CNN’s Tara Subramaniam contributed reporting