Sehgal has been diagnosed with the vector-borne disease and is undergoing treatment at the King George's Medical University (KGMU).
Chief medical superintendent, KGMU, SN Shankhawar said, "On Thursday night, the principal secretary's health deteriorated. At the same time his platelets were counted 10,000. For this reason, he has been admitted to the respiratory intensive care unit."
Besides, 18 dengue cases were reported on Friday, the authorities added.