Exit polls on Tuesday evening predicted a hung assembly in Maharashtra with the Congress-led alliance coming on top after millions voted during the day in three states including Haryana and Arunachal Pradesh.
The balloting was marred by the murder of a polling agent in Haryana and Maoist violence in Maharashtra, whose election outcome is expected to have a bearing on national politics.
Both Star TV and IBN-Lokmat exit polls suggested a split verdict in the 288-seat Maharashtra assembly with the Congress-Nationalist Congress Party (NCP) combine bagging the most number of seats.
Star said the Congress and NCP would end up with 140 seats -- five short of the halfway mark -- while IBN-Lokmat said the coalition would get 135-145 seats.
Political pundits said they expected the Shiv Sena-Bharatiya Janata Party (BJP) alliance to get 105-115 seats, mainly because Raj Thackeray's Maharashtra Navnirman Sena (MNS) had undercut their support base.
Thanks mainly to a splintered opposition, the Congress is expected to sweep Haryana and win in Arunachal Pradesh, the northeastern state that has been in the news because of Chinese claims over its ownership.
The Election Commission said 66 percent of around 90 million electorate voted in the three states, with 60 percent turnout recorded in Maharashtra and 72 percent in Arunachal Pradesh. Haryana's voting was 66 percent.
A victory of the Congress-NCP alliance over the Shiv Sena and BJP in Maharashtra, one of India's most industrialised states, will consolidate the Congress grip nationally after the Lok Sabha election when the party stunningly retained power.
Brisk polling was recorded in most places across the three states, the enthusiastic voters ranging from the poorest of the poor from urban slums to Bollywood's millionaire actors.
"I voted because it concerns our future, our children's future," Hindi movie star Aamir Khan told journalists after casting his vote early in the day in Mumbai, India's financial and entertainment capital.
But despite the prospects of a hung assembly in Maharashtra, the Congress ruled out joining hands with the vote-splitter MNS.
"We don't have any tie-up with Raj Thackeray at present, we didn't have any in the past and we won't have any in future as well," Congress general secretary Digvijay Singh said.
He insisted that the Congress would win over 85 and the NCP 60 seats. In 2004, the NCP won 71 and the Congress 69 seats. This time, the Congress is contesting from 174 and the NCP from 114 constituencies.
In Haryana, police said Jyoti Ram, the polling agent of an independent candidate, was killed in a clash in Hemu Majra village of Kaithal, 150 km from Chandigarh.
Reports of firing and clashes between Congress and Indian National Lok Dal (INLD) supporters came in from Nima Kheri and other villages in Mewat district. Four people were injured.
After voting Haryana Chief Minister Bhupinder Singh Hooda declared: "The Congress will sweep this elections." The Hooda government got the previous assembly dissolved seven months before its term was to end.
In Arunachal, Chief Minister Dorjee Khandu and two more Congress members have been elected unopposed. A total of 154 candidates were in the fray, with the Congress fielding candidates for all 60 seats.
"It was heartening to see people come out in large numbers. This is an indication that we are winning hands down once again," a confident Khandu told IANS.
Election results are slated to be declared on October 22.