Hundreds of thousands of police guarded some 200 million eligible voters across swathes of central and southern India, but no major trouble was reported. A week earlier, 16 people were killed in Maoist violence in the first phase of voting.
The ruling Congress party-led coalition appears to lead against an alliance headed by the Hindu-nationalist Bharatiya Janata Party, or BJP, but both may need the support of a host of smaller regional parties to win office. Under armed guard, Singh cast his vote in Guwahati, the principal city of the northeastern state of Assam which was hit by a string of separatist bombs in the run up to the election.
Singh is the prime ministerial candidate for the Congress party, which has overseen an economic boom since coming to power in 2004. But the outlook for the next government is less rosy due to a yawning fiscal deficit just as the economy suffers a downturn.
There is also speculation that a group of smaller parties known as the "Third Front," which are often seen as opportunist and an unknown quantity in government, could spoil the chances of the BJP or Congress. The second round of polling, the biggest of the five phases, involves people from India's rural heartland, the IT center of Bangalore and some states where Maoist rebels are strong.