Drone footage over parts of the Indian capital Delhi showed the city blanketed with a thick haze, which resident Ankit Kumar said caused irritation to the eyes and made it difficult to breathe.
"It is very bad for those people who are older in age, especially younger children also," he said.
New Delhi's air pollution typically worsens in October and November due to farmers burning agricultural waste, coal-fired power plants, traffic, and windless days.
Delhi's Chief Minister Arvind Kejriwal had banned the use and sale of firecrackers ahead of the Hindu festival of lights, but the policy has been difficult to implement.
The average pollution level in Delhi was nine times what the World Health Organization considers to be safe, but some defended the use of firecrackers saying they are an essential part of a religious tradition celebrated by millions across the country.