The fragility of the eurozone manufacturing sector was once again clear in the purchasing managers index for May, as manufacturing orders fell for the first time since June 2020, S&P Global said in a note.

The S&P Global manufacturing PMI fell to 54.6 in May from 55.5 in April. This is the lowest mark in 18 months.

“Eurozone manufacturers continue to struggle against the headwinds of supply shortages, elevated inflationary pressures and weakening demand amid rising uncertainty about the economic outlook,” Chris Williamson, chief business economist at S&P Global Market Intelligence, said in a note.

Although output growth picked up marginally from April’s low, it remained sluggish, while business confidence was among the lowest seen over the past two years amid sustained concerns surrounding the outlook for prices, supply chains and demand.

The manufacturing sector’s deteriorating health has also been exacerbated by demand shifting to services, as consumers boost their spending on activities such as tourism and recreation, Mr. Williamson said.

Prices data signaled still-substantial inflationary pressures in May despite rates of increase in both input costs and output charges easing slightly, the report said.

Write to Maria Martinez at maria.martinez@wsj.com