Jolly was almost hit by a water bottle, but he escaped unhurt, said Bishnu Rijal, press advisor of Madhav Kumar Nepal, former Nepal Prime Minister and one of the contenders for the post of chairman of the CPN-UML.
A journalist accompanied by Jolly was hit by the bottle.
"The UML cadres did not attack him intentionally, rather the bottle was thrown towards him accidentally," said Rijal.
"As Jolly was coming out of the main gate of Bhrikutimandap Exhibition Hall without any security escort, the students and youths, who were engaged in the squabble, mistakenly threw the bottle towards him," he said.
Jolly and Pallab Sengupta of CPI(M) were among the Indian representatives who attended the five-day meet.
There were a number instances of clashes between the supporters of KP Oli and Madhav Kumar Nepal, the two main contenders of the party chair while the inaugural function of the general convention was in progress.
The traffic was also jammed for half an hour due to the clash.
The two groups also threw stones and hit by stick on each other and the police had to baton charge to take the situation under control.