A total electorate of 12.79 crore is eligible to exercise their franchise in this phase covering 17 seats in Maharashtra, including Mumbai's six seats, six in Odisha, 13 in Uttar Pradesh, five in Bihar, and eight in West Bengal, while Rajasthan, Jharkhand and Madhya Pradesh have their first phase of polls with voting in 13, 3 and 6 constituencies, respectively.

Voting will also be held in the second phase of the staggered polling in Jammu and Kashmir's Anantnag constituency.

The phase will also see polling in the final phase of the Odisha Assembly elections as well the bypoll to Madhya Pradesh's Chhindwara Assembly seat from where Chief Minister Kamal Nath is contesting in order to become a legislator.

Prominent candidates in this phase include Union Minister Babul Supriyo (BJP), who faces yesteryear actor Moon Moon Sen (Trinamool Congress) in West Bengal's Asansol, his colleague Giriraj Singh (BJP), who faces former JNU student leader Kanhaiya Kumar (CPI) in Bihar's Begusarai, film actress Urmila Matondkar (Mumbai North), and Samajwadi Party President Akhilesh Yadav's wife Dimple Yadav (Kannauj).

Also contesting are Rajasthan Chief Minister Ashok Gehlot's son Vaibhav Gehlot (Jodhpur), his predecessor Vasundhara Raje's son Dushyant Singh from Jhalawar-Baran, and Kamal Nath's son Nakul Nath in Madhya Pradesh's Chhindwara.

In the fourth phase, the BJP will be defending 45 of the seats it won in the 2014 Lok Sabha battle -- 13 in Rajasthan, 12 in Uttar Pradesh, eight in Maharashtra, five in Madhya Pradesh, three in Bihar, three in Jharkhand and one in West Bengal.

In Maharashtra, all the remaining nine seats were won by the Shiv Sena while in Bihar, the remaining two seats were bagged by BJP's ally Lok Janshakti Party. The Congress got only two -- one in Madhya Pradesh and one in West Bengal.

Among other parties, the Biju Janata Dal won all six in Odisha, the Trinamool Congress six in West Bengal and the Samajwadi Party one in Uttar Pradesh.

With the fourth phase, voting will be completed in all seats of Maharashtra and Odisha.

The seven-phase Lok Sabha elections started on April 11 and would conclude on May 19. Counting of votes will take place on May 23.