Thousands voted on Saturday in the Vaishali Nagar assembly constituency in Chhattisgarh, with the ruling Bharatiya Janata Party (BJP) hoping to retain the seat despite a strong Congress challenge.
Up to 30 percent of about 211,000 voters had exercised their franchise by noon, an official said.
Women outnumbered men at polling booths in urban areas of Vaishali Nagar in Durg district even before voting began at 8 a.m. Balloting picked up in rural areas after a dull start.
Officials reported peaceful voting in most of the 221 polling booths. The main contest is between the BJP's Jageshwar Sahu and Bhajan Singh Nirankari of the Congress.
The by-poll was necessitated after BJP legislator Saroj Pandey was elected to the Lok Sabha in May. She won the assembly seat in November 2008.