Prasad was sipping tea at the dais, while a speaker was delivering his speech at the poll rally, when the mishap occurred.
Prasad had pointed to the organisers that the fan was rotating dangerously and before anything could be done, it fell on his right hand spilling the tea.
The RJD chief, who escaped with minor injuries, stayed put at the dais and later addressed the election meeting at Lakhaura High school here.
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He was campaigning for RJD candidate Binod Shrivastava contesting from Motihari seat.
Later, addressing the meeting, Prasad came down heavily on the organisers and the electrician for improper arrangement.
He jokingly told the crowd that he enjoyed blessings of Goddess 'Sherawali' (Durga) and hence no harm could happen to him.
Prasad met another accident just two days ago at Arwal when a portion of the dais, put up for an election meeting, collapsed due to overloading. He was unhurt.