BEIJING—Searing heatwaves swept across China’s vast Yangtze River basin on Wednesday, hammering densely populated megacities from Shanghai on the coast to Chengdu deep in the heartlands.
More than 90 red alerts, the most severe in a three-rung warning system, were active across China as of 3:30 p.m. Most were in the Yangtze basin, which spans nearly 2,000 kilometers (1,200 miles).
