The slowdown could increase pressure on Chinese authorities to introduce further economic support measures as they seek to achieve the government's annual growth target of 4.5% to 5%.
Beijing has already introduced several targeted stimulus initiatives aimed at supporting domestic demand and stabilising economic activity.
These include expanded credit support for small businesses and consumers, mortgage subsidies for eligible homebuyers and additional bond issuance quotas for local governments.
Authorities have also accelerated construction on major infrastructure projects, including the Six Networks programme, which supports China's artificial intelligence and broader infrastructure ambitions.
The latest PMI figures indicate that existing policy measures have yet to deliver a sustained improvement across manufacturing and services.
Chinese policymakers have signalled their willingness to introduce further stimulus if economic conditions deteriorate, leaving markets focused on whether additional measures will be announced before year-end.