Underworld don Rajendra Nikalje alias Chhota Rajan was admitted to the All India Institute of Medical Sciences (AIIMS) in Delhi on July 27, reported news agency ANI.
According to ANI, Chhota Rajan complained of ill health after which he was admitted to AIIMS. He is currently undergoing treatment at the hospital.
Earlier in April, Chhota Rajan was admitted to AIIMS after he tested positive for COVID-19.
He is lodged in the high-security Tihar prison in New Delhi since his arrest after deportation from Bali, Indonesia, in 2015.
All the criminal cases pending against him in Mumbai were transferred to the CBI and a special court was constituted to try them. Chhota Rajan is facing as many as 70 criminal cases pertaining to extortion and murder in Mumbai.
On Wednesday, the Central Bureau of Investigation (CBI) opposed Chhota Rajan's bail plea in the Bombay High Court and said the gangster had no respect for the country's laws.
Special Public Prosecutor Pardeep Gharat told a single bench presided over by Justice Anuja Prabhudesai that Rajan had multiple cases pending against him and was convicted and sentenced in a host of other cases.
Gharat urged the high court not to grant bail to Rajan, saying the gangster was a "Z plus security threat".
He said Rajan had fled India and travelled to several other countries on fake names and passports before he was finally arrested and extradited to India in November 2015.
(With input from PTI)