The Trump administration is using the country’s vast and nearly opaque immigration bureaucracy to constrict the flow of foreign workers into the United States by throwing up new roadblocks to limit legal arrivals.

The government is denying more work visas, asking applicants to provide additional information and delaying approvals more frequently than just a year earlier. Hospitals, hotels, technology companies and other businesses say they are now struggling to fill jobs with the foreign workers they need.

With foreign hires missing, the employees who remain are being forced to pick up the slack. Seasonal industries like hotels and landscaping are having to turn down customers or provide fewer services. Corporate executives worry about the long-term impact of losing talented engineers and programmers to countries like Canada that are laying out the welcome mat for skilled foreigners.

At Northwell Health’s pathology lab on Long Island, a new doctor’s cubicle stands empty, her computer and microscope untouched. Other residents started on July 1, but she is stuck in India’s Punjab State, held up by unexplained delays in her visa.