Bye-elections from 20 assembly constituencies in six states and Delhi will be held on Thursday with a focus on Gujarat where the outcome would be seen as a popularity test for Chief Minister Narendra Modi.
Seven of the constituencies are in Gujarat, seven in Bihar, two in Madhya Pradesh and one each in Uttarakhand, Sikkim and Delhi.
In Gujarat, bye-elections will be held in Chotila, Jasdan, Dhoraji, Kodinar, Dahegam, Sami and Data constituencies of Saurashtra and north Gujarat regions due to various reasons, including some legislators getting elected to the Lok Sabha in April-May polls.
Modi had claimed that his Bharatiya Janata Party (BJP) would fetch 24 of the 26 Lok Sabha seats from the state in the April-May elections, but ended up winning only 15 seats - only one more than what the party had in the 2004 elections.
Modi received another setback when his party lost a crucial municipal corporation election in its stronghold of Junagadh city last month.
In Bihar, bye-elections will be held for the assembly seats of Bochaha, Warisnagar and Chenari (all Scheduled Castes), and Aurai, Kalyanpur, Ramgarh, and Chainpur.
Buoyed with its success in the Lok Sabha elections, the Congress has decided to contest the Bihar by-polls on its own, having cold-shouldered overtures of Rashtriya Janata Dal (RJD) chief Lalu Prasad and Lok Janshakti Party (LJP) president Ram Vilas Paswan.
The BJP and the Janata Dal-United (JD-U) have an alliance that is ruling the state.
In Madhya Pradesh, bye-elections would be held for Gohad and Tendukheda constituencies. In Andhra Pradesh, Tekkali constituency will go to the poll.
In Sikkim, Namchi Singithong and in Uttarakhand Vikasnagar will go for bye-elections.
In Delhi, the by-poll will be held for the Dwarka seat after sitting legislator Mahabal Mishra (Congress) became an MP.