The police took a suo motu action and registered a case in connection with the incident that took place on August 24 between 3 to 3.30 PM.
However, the matter came to light after a person posted pictures of the bill board on the social media, they said.
"Since images of the bill board streaming a porn clip went viral on the social media, we decided to register a case against the technician," said Inspector Sucheta Khokale of Deccan Gymkhana police station.
The bill board suddenly started streaming the porn clip and some commuters clicked its pictures, Khokale said.
As per the inspector, the police are verifying whether it was done intentionally or it happened by accident.
A traffic police constable, who was posted at the junction, said the clip was streamed for hardly for few seconds.