The world's largest election began on April 19 and will conclude on June 1, with votes set to be counted on June 4.
Monday's phase has the least number of seats being contested, with 89.5 million voters set to choose representatives for 49 seats.
Several high-profile candidates are in the fray on Monday - including defence minister Rajnath Singh from Lucknow and trade minister Piyush Goyal from Mumbai - cities which have suffered from a dismal voter turnout in the past.
The Election Commission specifically called upon residents of those cities "to erase the stigma" of urban apathy.
"At the core of our vision for Mumbai is - better infrastructure and more 'ease of living," Prime Minister Narendra Modi said while campaigning in the city, just days after at least 14 people were killed when a massive billboard fell during a rainstorm.
Two boroughs of the Congress party's Nehru-Gandhi dynasty in the politically-crucial Uttar Pradesh are also going to polls, with scion Rahul Gandhi contesting the seat of Raebareli, in addition to Wayanad in the south which has already voted. India allows candidates to contest multiple constituencies but represent only one.
Sonia Gandhi, Congress party chief and former lawmaker from Raebareli, made an emotional appeal to voters asking them to vote for her son in a region that the Bhartiya Janata Party (BJP) has dominated in the last 10 years.
Smriti Irani, minister for women and child development, is contesting from Amethi. In 2019, she defeated Rahul Gandhi in a seat his family held continuously for the last four decades.
Among other keenly watched electorates in the state is Kaiserganj, where the BJP is fielding a former wrestling federation chief's son, despite his father being charged with sexually harassing female wrestlers.
Poor voter turnout became a concern for the ruling BJP initially, and analysts believe the low numbers cast doubts on the landslide victory the party and its allies sought.
After an initial poor performance, more people started casting their vote with an average turnout of 66.95 per cent in four phases, and 69 per cent in the fourth one on May 13.
Modi, widely expected to return as prime minister for a third consecutive term, has been accused by opponents of targeting minority Muslims to please hardline voters.
Modi has repeatedly accused the Congress party of planning to extend welfare benefits to Muslims at the expense of disadvantaged tribal groups and Hindu castes, a claim the Congress has denied.
In a recent television interview aired after the fourth phase, Modi said it was his resolve to "not do Hindu-Muslim (in politics)".
The opposition INDIA alliance, consisting of Congress and a dozen political parties, received a major boost after fierce Modi critic and Chief Minister of Delhi Arvind Kejriwal was given temporary relief by the court and allowed to campaign in the elections.
