Six dead in Tokyo as Japan swelters in heatwave

Over the weekend, the central Shizuoka region became the first in Japan to see the mercury reach 40 degrees Celsius this year, far surpassing the 35-degree threshold classified by weather officials as "extremely hot".

Such severe heat in the middle of Japan's rainy season is "rather rare", caused in part by a strong South Pacific high-pressure system, a weather agency official said.

Temperatures also hit record highs near 40 degrees Celsius on Monday at observation posts in Tokyo and in the southern Wakayama region, according to local media.

The past few days have seen authorities issue heatstroke alerts in most parts of the country, urging residents to avoid exercising outside and to use air conditioning.

The capital logged three deaths linked to heatstroke on Saturday and three more on Monday, when the mercury hovered around 35 degrees Celsius at midday, according to the city's medical examination office.

"Without the AC on, I find it difficult to survive," Tokyo resident Sumiko Yamamoto, 75, told AFP, adding she feels "it's gotten drastically hotter" since last year.

"Through the advice given on TV, I try to stay hydrated as much as possible. Because I'm old, I'm being careful not to collapse," she said.

Heatstroke is particularly deadly in Japan, which has the second-oldest population in the world after Monaco.

Yamamoto's age puts her in the demographic flagged by health experts as particularly vulnerable to heatstroke, along with infants and those living alone or who are too poor to afford air conditioning.