NEW DELHI (AP) — As India prepares for Diwali, the Hindu festival of lights, people are divided over whether to set off fireworks to celebrate, worsening the country’s chronic air pollution.

Diwali, celebrated on Thursday, is all about socializing and exchanging gifts with family and friends. Many Indians light earthen oil lamps or candles. But every year the celebrations are marked by concerns about air pollution, as smoking fireworks create toxic smog that can take days to clear.

The capital New Delhi, which is among India’s cities with the worst air quality, is particularly affected by the problem and is usually shrouded in toxic gray smog the day after Diwali. Authorities there and in some other states have banned the use and sale of fireworks since 2017 and urged people to choose more sustainable options such as eco-friendly fireworks and light shows, but the rule is often flouted. Firecrackers can easily be purchased from street stalls and shops.

Some New Delhi residents say the ban doesn’t make much of a difference, while others see it as a necessary measure to combat pollution.

Vegetable seller Renu, who uses only one name, loves celebrating Diwali in the city. Every year their children set off fireworks at night. She tells them to be careful but not to refrain from using them.

“Diwali for us is a day of celebration and joy that comes only once a year and I feel there should be no ban there,” she said.

Others are against it.

Unlike most children, Ruhaani Mandal, 13, doesn’t light fireworks. She admits it’s fun, but says it’s dangerous for people and animals.

“I have seen first-hand the struggle of my father, who lost his sense of smell due to pollution, and I see his health deteriorating after Diwali celebrations,” she said.

New Delhi and several northern Indian cities typically experience extremely high levels of air pollution between October and January each year, leading to business disruptions and the closure of schools and offices. Authorities are closing construction sites, banning diesel-powered vehicles and using water sprinklers and anti-smog guns to control the haze and smog that shrouds the skyline.

This year, thick, toxic smog has already begun to engulf New Delhi. On Wednesday, authorities reported an AQI of over 300, which is considered “very poor.”

Several studies estimate that more than a million Indians die from air pollution-related diseases every year. High levels of tiny particulate matter can lodge deep in the lungs and cause serious health problems, including chronic respiratory diseases.

The problems in New Delhi are not just due to fireworks. Vehicle emissions, fires on farms in neighboring states and construction dust are the main causes of air pollution in the capital. But health experts say smoke from fireworks can be more dangerous.

“The smoke produced by firecrackers contains heavy metals like sulfur, lead and toxic gases like carbon monoxide and heavy metal fumes, which are dangerous for our respiratory system,” said Arun Kumar Sharma, professor of community medicine at the University College of New Delhi Medical Sciences.

Meanwhile, authorities in New Delhi have largely failed to enforce a strict ban on the use of fireworks to avoid offending millions of Hindus across the country, for whom Diwali is one of the biggest festivals. To get around the ban, many sellers are offering fireworks online, some even offering convenient home delivery.

Shop owner Gyaanchand Goyal said the ban on firecrackers has penalized vendors like him and affected their biggest source of income during the festive season.

“The government is forcing a restriction on fireworks just to demonstrate its commitment to the environment. Apart from that, I don’t think this ban has any further consequences,” he said.