The Short Version
The available evidence does not substantiate the claim that industrialist Aditya Birla was physically manhandled in Kolkata. The only sources explicitly alleging the incident are low-authority opinion blogs lacking primary documentation, named witnesses, or contemporaneous reporting. Higher-credibility mainstream sources in the evidence pool either address unrelated Birla matters or discuss general industrial migration from West Bengal without mentioning any assault on Aditya Birla personally. The claim may reflect political folklore surrounding Bengal's industrial decline, but it cannot be treated as established fact.