The voting for the by-polls for four Assembly seats in Bawana in Delhi, Nandyal in Andhra Pradesh, and Valpoi and Panaji in Goa has begun.
The polling, being held at 76 booths, including 30 in Panaji and 46 in Valpoi, will continue till 5 p.m.
The four Assembly seats fell vacant owing to different reasons.
The Nandyal seat in Andhra Pradesh fell vacant after the Telugu Desam Party (TDP) legislator passed away following a cardiac arrest.
The TDP has fielded YSR Congress Party chief Jaganmohan Reddy’s nephew Brahmananda Reddy, while the YSRCP has put up former minister Silpa Chandra Mohan Reddy, who lost the seat as a TDP nominee in 2014.
Goa Chief Minister Manohar Parrikar is contesting from the Panaji constituency against Congress vice-president Rahul Gandhi’s confidante Girish Chodankar.
In the Valpoi contest, Health Minister Vishwajeet Rane is in fray against Roy Naik, the son of former state Home minister Ravi Naik, of the Congress.
The Bharatiya Janata Party (BJP) has fielded Ved Prakash in the Bawana constituency, who won in 2015 Assembly elections as an AAP candidate. He resigned in March to join the saffron party.
The Voter Verifiable Paper Audit Trail (VVPAT) machines would be used today.
The by-polls results will be declared on August 28.