Over 51 per cent polling has been reported in the fourth phase of assembly elections in Bihar today. Speaking to reporters in New Delhi, Deputy Election Commissioner Vinod Zutshi said the polling was peaceful barring a few minor incidents.Over 46 per cent polling was reported in the bye-election to the Banka Lok Sabha seat. Besides other tight security measures, Mr Zutshi said, four helicopters were also pressed into air surveillance. He said a case has been registered against RJD leader Lalu Prasad for violating the norms of Election Commission.FIR was also registered against former Chief Minister Rabri Devi for viloating EC norms.AIR correspondent K.K. Lal reports from Patna that the Bihar administration heaved a shy of relief after peaceful poll in the naxal affected areas.Polling parties are depositing EVMs in their respective strong rooms. The Election Commission has instructed all poll related officials to be vigilant even in the night. Strict vigil is being maintained in sensitive areas to avert untoward incident. Patrolling continues to be intensified during the night also. After completion of the fourth phase of elections polling has been completed in 182 constituencies out of 243.