Muralidharan had appealed to the Switzerland-based CAS against the decisions of Anti-Doping Disciplinary Panel (ADDP) and Anti-Doping Appeal Panel (ADAP) of the NADA after his test sample taken during National Aquatic Championships in Jaipur in August 2010 was found to contain prohibited substances.
The 30-year-old Muralidharan is a former national champion in 200m freestyle and butterfly and he also won a silver in 4x200m freestyle relay in 2003 Afro-Asian Games in Hyderabad.
The CAS also found typographical errors in the document package produced by National Dope Testing Laboratory (NDTL).
Muralidharan filed an appeal at the CAS in June last year against the NADA, NDTL and Sports Ministry, arguing that the challenged decisions should be annulled on the grounds that his sample had not been processed in accordance with the NADA Anti-Doping Regulations and WADA International Standard for Testing, and should therefore be nullified.
"This case was heard on January 16, 2015. Based on the evidence, the Sole Arbitrator found the errors evident in the document package produced by the laboratory were purely typographical and had no impact on reliability or integrity of the sample," the CAS said in a statement on its website.
"The errors, while indeed unfortunate and avoidable, were not so fundamental as to call into question the laboratory's compliance with the IST thereby nullifying the positive sample. Furthermore, the Sole Arbitrator found that while the NADA's delays in handling the athlete's case were excessive, such delays did not fundamentally violate Mr Muralidharan's procedural rights," it said.
