It was 96 degrees in the shade with high humidity and not a breath of wind on Tuesday afternoon in a factory district in Guangzhou, the home base of China’s garment manufacturing.

The sewing workshops that were operating in one neighborhood were sweltering. But roughly half of the hundreds of factories were dark, with their doors closed and none of their usual bustle. Around the area, bright red signs on walls and poles indicated industrial buildings were available for sale or rent.

After exchanging escalating tariffs and export restrictions in the spring, China and the Trump administration moved closer this week to another cease-fire to continue to negotiate over their myriad conflicts. But the new status quo has left high barriers between China’s exporters and some of their biggest markets in the United States.

Guangdong Province, in southeastern China, and its capital, Guangzhou, have borne the brunt of Mr. Trump’s tariffs. China’s coastal export sector has been hit twice. It is paying tariffs of 30 percent or more on shipments to the United States — extraordinarily high by historical measures — on top of previous tariffs. And exporters to the United States no longer enjoy duty-free treatment for packages worth $800 or less.

In Guangzhou, thousands of small factories near the Pearl River used to supply the cheap clothing that e-commerce giants like Shein and Temu shipped to American homes. Streets in the city’s factory districts are less crowded, while managers and workers complain that many orders have evaporated.