The Sir Ganga Ram Hospital (SGRH) had earlier said that she was admitted for 'routine tests and investigations'.
She was admitted to the private facility in New Delhi at 7 pm for 'routine tests and investigations', the hospital said in a health bulletin.
She was down with viral fever and doctors advised her to be under medical supervision.
Her medical condition was stable and she has been advised rest.
Gandhi underwent a surgery on her left shoulder on August 3 and doctors said she almost recovered from the injury.
Sir Ganga Ram Hospital, where she has been admitted, said all her health parameters are showing improvement and she was shifted out of the ICU.
Congress President Sonia Gandhi, who has been hospitalised for lower respiratory tract infection, is stable and recovering well.
She had to cut short her roadshow in Varanasi after she was taken ill. She had fractured her left shoulder during the roadshow.
'Mrs Sonia Gandhi, chairperson, UPA has been admitted to our hospital today. She has been admitted in Department of Chest Medicine under the care of Dr Arup Basu and his team. Mrs Gandhi has been admitted for observation and treatment of a viral respiratory infection,' said Dr Ajay Swaroop, chairman of the hospital's board of management.
She came for removal of her stitches from the surgery, a hospital source said.
The transplant surgery was performed recently at the Sir Ganga Ram Hospital in central Delhi.
Observing that working conditions have made doctors and health professionals susceptible to violence, the Supreme Court on Tuesday constituted a 10-member task force to formulate a national protocol for ensuring safety and facilities for them in the wake of the rape and murder of a medic in Kolkata.
Chikungunya cases in the national capital have sharply risen to over 1,000 this season.
The bench said the Union Cabinet Secretary will be the convenor of the task force and may nominate an officer not below the rank of Additional Secretary to depute for him, when necessary.
Delhi's air quality deteriorated significantly on Monday, with areas like Dwarka, Mundka and Najafgarh recording an AQI of 500, the worst this season. The city's overall AQI reached 491, triggering the implementation of the Graded Response Action Plan (GRAP) Stage-IV restrictions in Delhi-NCR. Doctors warned of health risks, urging people to wear N95 masks and avoid outdoor activities. The Supreme Court questioned the Delhi government on its anti-pollution measures and warned against scaling down preventive measures without its permission. Delhi Chief Minister Atishi accused the BJP-led central government of political maneuvering while neglecting stubble burning in states it governs. Meanwhile, the city enforced stricter pollution control measures, including a ban on truck entry and suspension of construction activities. Air purifier sales surged, reflecting the public's concern over the severe air pollution.
Gill was suffering from end-stage kidney failure and significant ischemic heart disease. He was recovering from peritonitis.