The Election Commission said the exercise all over was peaceful. In Delhi, a police officer told IANS: "All is under control."
In Bihar, however, two Central Reserve Police Force (CRPF) personnel were killed when Maoists exploded a concealed land mine in Munger district when they were on their way to neighbouring Jamui where polling was on.
A total of 1,414 candidates are in the fray Thursday, the third round of staggered national election that began April 7 in the country's northeast.
Thursday's balloting covered all 20 Lok Sabha constituencies in Kerala, 10 each in Uttar Pradesh, Haryana, Maharashtra and Odisha, nine in Madhya Pradesh, all seven seats in Delhi, six in Bihar, four in Jharkhand and one each in Chhattisgarh, Jammu, Chandigarh, Lakshwadeep as well as Andaman and Nicobar Island.
Congress president Sonia Gandhi, her son and party vice president Rahul Gandhi and AAP leader Arvind Kejriwal voted in separate polling centres in the national capital. Former BJP president Nitin Gadkari voted in Nagpur.