July was a bad month for Tesla in Europe and a good one for BYD. It might signal that the tides are turning toward BYD as the top EV company in the world.

Tesla Inc. continues to post steep sales declines in Europe, where the Elon Musk-led automaker is ceding significant share to China’s BYD Co.

Tesla Inc.’s rough stretch in Europe continued as data from Germany and the U.K. showed the U.S.-based electric-vehicle maker’s sales were cut in half last month.