India's weather bureau said on Thursday that extreme heat conditions will continue in many states till the weekend.
This includes parts of the eastern state of Bihar, where five districts will go to polls on Friday and which recorded temperatures 5.1 degrees Celsius above the seasonal average this week.
The state of Karnataka in the south and parts of Uttar Pradesh, India's most populous state and a bastion of the Hindu faith, are also set to vote as they face heat wave conditions.
Earlier this week, the Election Commission of India said it had formed a task force to review the impact of heat waves and humidity before each round of voting.
The Hindu newspaper suggested that the decision could have been taken due to concerns that the extreme heat “might lead to a decline in voting percentage”.