He had recovered from COVID-19 late last month, they said.
There have been three cases of post-COVID black fungus infection at the hospital. The first two cases were reported in January and February this year.
All three patients had to undergo surgeries, they said.
Chief Medical Superintendent of the hospital Rahul Prasad said people with diabetes and weak immunity are vulnerable to the infection which first affects the eyes and can be fatal if it spreads to other parts of the body.
COVID-19 patients who have co-morbidities like diabetes need to be very careful even after recovery to keep mucormycosis at bay, Prasad said.