A relentless heatwave is disrupting daily life and putting urgent pressure on authorities to respond in parts of China, Japan and South Korea. In northwest China temperatures could exceed 40°C, and local authorities in some cities are opening up air raid shelters to allow the public to cool in air-conditioning. In South Korea, the highest heat alert level has been expanded to 43% of the greater Seoul area. At least 19 people in the country have died and more than 2,000 hospitalised with heat-related illnesses since May. Meanwhile, in Japan, more than 9,000 people have been treated for heatstroke. Tan Si Hui, Lim Yun Suk and Michiyo Ishida report.