- Yadav "devastated" that dream has been "cruelly snatched away"
- Indian wrestler Narsingh Yadav receives 4-year ban for doping
- The 27-year-old was originally cleared after he claimed his food was spiked
The decision marks the end of a tumultuous road to Rio for the 27-year-old, who was originally suspended from competing at the Olympic games following two positive anti-doping tests for a banned steroid in June and July this year.
The 74kg wrestler says he is devastated at the decision and will do everything it takes to prove his innocence.
"My dream of competing and winning the country a medal at the Rio Olympics has been cruelly snatched away from me twelve hours before my first bout," he said in a statement.
Yadav was initially exonerated by India's National Doping Agency after he successfully argued he was the victim of sabotage.
He claimed his food and drink had been tampered with.
But the World Anti-Doping Agency (WADA) urgently appealed the all-clear ahead of Yadav's opening bout Friday, and the CAS panel did not accept the athlete's argument that he was the victim of a conspiracy.
"There was no evidence he bore no fault, nor that the anti-doping rule violation was not intentional," CAS said in a statement. "The standard 4-year period of ineligibility was imposed by the Panel."
The ban ends any hopes of Yadav's comeback on the world stage. The wrestler had previously qualified for the 2012 Olympics but was ousted in the opening round.
"This is conspiracy against him, and a sabotage," Brij Bhushan Sharan Singh, Wrestling Federation of India president, told local media
"We will have to return to India and explore legal options."