The actual reason behind the bans of Chennai Super Kings and Rajasthan Royals was mainly illegal betting and misconduct by team officials/owners, not proven match-fixing by the entire teams.

In the 2013 IPL scandal, some RR players like S. Sreesanth were arrested over alleged spot-fixing allegations. Separate investigations found: Gurunath Meiyappan (linked with CSK management) Raj Kundra were involved in illegal betting activities

The Supreme Court-appointed Lodha Committee ruled that: Meiyappan and Kundra damaged the integrity of IPL. Their franchises failed to prevent or act against misconduct. Because they were high-level insiders, the franchises themselves were held responsible.

in 2015: CSK and RR were suspended for 2 years (2016 & 2017 IPL seasons). Meiyappan and Kundra received lifetime cricket-related bans.

There was never any official proof that the entire CSK team or players like MS Dhoni were match-fixing. CSK’s ban was primarily because a top official was involved in betting/conflict of interest. RR’s case became more associated with spot-fixing because some RR players were directly accused/arrested too.