Rajya Sabha member and former Samajwadi Party leader Amar Singh was on Monday evening admitted to the All India Institute of Medical Sciences (AIIMS) by Tihar Jail authorities for a kidney-related problem.
According to sources at the hospital, Singh was admitted in a private ward of the hospital.
He arrived at around 7 pm and was admitted to ward 218.
"His treatment has started and tests have started," a hospital source said, declining to be named.
Special Judge Sangita Dhingra Sehgal on Monday reserved hearing on Singh's interim bail plea in the cash-for-votes scam till Tuesday.
Amar Singh and two former Bharatiya Janata Party (BJP) MPs - Faggan Singh Kulaste and Mahavir Singh Bhagora - were arrested on Sep 6 for their alleged involvement in an attempt to bribe MPs ahead of the July 2008 parliament trust vote.