The first jallikattu in Tiruchi district this Pongal season got underway at Periya Suriyur village on the city's outskirts on Thursday amid heavy police bandobust.
Around 600 bulls from various districts have been registered for the event with the number of tamers being over 330.
The event was inaugurated by District Collector Sivarasu in the presence of Superintendent of Police Ziaul Haque and Animal Welfare Board officials.
Nine persons including five visitors and one tamer were injured up to 12 noon, said police sources.
Veterinary teams to screen the participating bulls were deployed at the venue. Every animal was being screened to check if he had been fed with alcohol, said a senior Animal Husbandry department official.
Separate medical teams have been deployed to screen the tamers and check their health condition prior to allowing them to take part.
Police and veterinary teams have also been posted at the collection point at the end of the arena where the released bull is captured by its owner.
A slew of surveillance cameras have been installed at vaadivasal from where the bull is released one after the other.
Police personnel from neighbouring Ariyalur district has been drawn to augment manpower strength.
Over 240 bulls had been released till noon and the event is expected to get over by 3 p.m. Four among the injured have been referred to the Mahatma Gandhi Government Hospital.