In Bihar, polling is progressing smoothly for the fourth phase of assembly elections and Banka Lok Sabha seat amidst tight security. Voting is taking place in 42 Assembly constituencies spread over eight districts. By-election to Banka parliamentary constituency was necessitated following the death of sitting MP Digvijay Singh. Over one crore electorates will decide the fate of 568 candidates including 58 women in this phase. Seven candidates are in the fray for Banka Parliamentary seat. The polling, which start at 7 am, will continue till 5 pm except in 14 naxal affected assembly segments where it will end at 3 pm. Central para military forces have been deployed at all booths to ensure free and fair poll. Inter-district border has been sealed to prevent any infiltration of anti social elements. Four BSF helicopters have been pressed into service for air surveillance. Election Commission has appointed Observers and Micro Observers to oversea the polls.