The decision comes in the backdrop of Supreme Court judge Markandeya Katju writing a letter to Prime Minister Manmohan Singh urging him to help in release of the ailing virologist from Karachi.
Gehlot has approved the mercy petition of Chishty, who is serving life imprisonment in Ajmer jail here, and has forwarded it to the state Governor for consideration, according to an official here.
The petition was cleared on "humanitarian grounds" on Friday and was forwarded to Raj Bhawan for approval of the (acting) Governor Shivraj Patil, the official said.
Chishty`s relatives and human rights activists had filed the mercy petition on Chishty`s behalf before the home department in April this year with a request the matter be dealt with expeditiously as his health was failing. The Chief Minister gave priority to the issue, he said.
The approval of the Governor, who has power under article 161 of the Constitution of India to remit a sentence, will pave the way for his release, the official said. Patil is out of the state and is scheduled to arrive this evening.
A session court in Ajmer had awarded Chisty life sentence on January 31, this year, in a murder case after an 18-year trial. He had filed an appeal in the High Court but his bail plea had been rejected.
Chishty, who was an Professor of Virology in Karachi Medical College, holds a PhD from Edinburgh University.
Chishty had got involved in a fracas during his visit to Ajmer in 1992 to meet his ailing mother and in the melee one person was killed leading to his arrest.
During the trial period, the sessions court, which had granted him bail, had ordered Chishty not to leave Ajmer and he was re-arrested after his conviction. He was sentenced to life imprisonment on January 31, this year.
Khalil, 78, is currently lodged in the hospital of central jail in Ajmer. According to his relatives and social activists, Khalil as a teacher has served in Saudi Arabia, the UK, Iran, Nigeria and Sri Lanka.