Deposing before Special CBI Judge O P Saini, Ruia alleged that the telecom business is highly competitive and some of the prosecution witnesses, who had recorded their statements before the court, might have been influenced by rival firms.
Ruia also claimed that clause 8 of unified access service licence (UASL), which according to CBI was violated by the accused facing trial in the case, was misunderstood and many of the facts were not appreciated during the probe.
He also alleged that he had no knowledge of the day-to-day functioning of Loop Telecom Ltd, one of the accused firm in the case.
Essar Group promoters Ravi Ruia and Anshuman Ruia, Loop Telecom promoters Kiran Khaitan, her husband I P Khaitan and Essar Group Director (Strategy and Planning) Vikash Saraf are facing trial in the case along with three firms Loop Telecom Ltd, Loop Mobile India Ltd and Essar Tele Holding Ltd.
CBI, in its charge sheet, had alleged that promoters of Essar Group and Loop Telecom had deliberately violated UASL guidelines by making "false and dishonest impression" before Department of Telecommunication (DoT) to get the 2G spectrum.
During the day's proceedings, the court also concluded the recording of statements of Kiran Khaitan and Anshuman Ruia.
Kiran Khaitan told the court that she was only a housewife and not aware of the functioning of Loop Telecom.
She also said she was shocked that a case was made against her and told the judge that no prosecution witnesses had deposed against her in particular.
The court also commenced the recording of the statement of I P Khaitan which will continue tomorrow.
The stage for recording of statements of the eight accused was set earlier when the court had given a draft questionnaire having 645 questions each and running into 308 pages to them.
During the recording of evidence in the case, which had commenced on July 26, 2012, the court had recorded the statements of 95 CBI witnesses, which run nto 1,056 pages.
In the case involving promoters of Essar Group and Loop Telecom, the court had framed charges against them for the offences under section 120 B (criminal conspiracy) read with section 420 (cheating) of the IPC while the substantial charge of cheating was made out against Saraf only.
All of them have denied the charges levelled by CBI in the case, arising out of the probe into the 2G spectrum scam.
CBI had filed the charge sheet against them on December 12, 2011 following its probe into the 2G spectrum allocation scam during the tenure of former Telecom Minister A Raja.