Japan saw 10,804 heatstroke sufferers taken to hospital by ambulance in the week through Sunday, a new weekly record this year, according to the Fire and Disaster Management Agency.
The figure far surpassed the previous week's 5,309 amid a heat wave pushing up temperatures to 35 degrees Celsius and beyond in various parts of the country.
Tokyo's 1,099 was the largest number of such heatstroke sufferers. Saitama came second, with 750, followed by Hokkaido, where the reading jumped 2.8-fold to 690.
The agency is calling on people to use air conditioners and fans without hesitation and to stay hydrated.
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