Many successful inmates go on to become yoga instructors
Prisoners in the Indian state of Madhya Pradesh are being freed early if they complete yoga courses.
For every three months spent practising posture, balance and breathing the inmates can cut their jail time by 15 days.
The authorities say the lessons help to improve the prisoners' self-control and reduce aggression.
Some 4,000 inmates across the state are benefiting from the scheme, and many go on to become yoga instructors.
The state's inspector general of prisons, Sanjay Mane, said: "Yoga is good for maintaining fitness, calming the behaviour, controlling anger and reducing stress.
"When a prisoner attends yoga sessions and fulfils some other conditions, he will be considered for a remission if his jail superintendent recommends his case."
Prisoners can also gain credit for attending adult literacy courses or studying for degrees.
An inmate at Gwalior central jail, Narayan Sharma - who has now moved on to become an instructor - says it helps to banish the "angry thoughts" in his mind.
"It was these thoughts that made me commit crimes," he said.
"I hope that after we are released, we can use what we have learned and promote yoga in society so that people no longer commit crime."