Germany’s auto industry is sliding faster into decline, with weak demand, trade tensions and rising Chinese competition compounding the pressures on the country’s carmakers.

Porsche on Thursday joined BMW AG and Mercedes-Benz Group in reporting weaker sales in China, where local competitors led by BYD Co. and Xiaomi Corp. are winning over buyers with competitively priced electric vehicles. BMW earlier this week cut its earnings outlook after demand in the world’s biggest auto market fell short of expectations.

The China struggles add to U.S. tariff costs and stagnant sales in Europe, squeezing Germany’s carmakers across their three core markets. Despite pouring billions of euros into battery technology, their first wave of EVs failed to gain traction, with next-generation models not arri

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