Firecrackers are central to Diwali celebrations for millions of Indian Hindus and this year has been no different, even as some cities, including New Delhi, have banned their use to reduce some of the world’s worst pollution levels.

Diwali honors the victorious return of Lord Rama, one of Hinduism’s most revered figures, and was celebrated in India on Thursday. It is also known as the Festival of Lights to symbolize the triumph of light over darkness or good over evil, explaining why fireworks are so central to the celebrations.

“Firecrackers damage the environment, but they are a way to bring us good luck,” said Yash Gadani, a local business owner in Ahmedabad, a city in western Gujarat state.

Although the bans have not stopped people from using firecrackers, factories that make the devices say their sales have plummeted this year as rising costs of living, including firecracker prices, have dampened the request.

In the village of Vanch, near Ahmedabad, thousands of workers covered in silver powder make firecrackers by hand.

The industry is largely informal with lax safety standards. Almost all of Vanch’s 10,000 residents are involved, and workers are paid 500 rupees ($5.95) a day, often for 16 hours a day.

“A few fires in factories along with unusual rains have led to an increase in prices of raw materials,” said Dipan Patel, who heads a unit in Vanch.

The ban on firecrackers has been difficult to implement, particularly during Diwali, despite threats of jail and fines.

New Delhi, a city of 20 million inhabitants, is the most polluted capital in the world. Every year from October onwards, air quality deteriorates as factors such as post-harvest agricultural stubble burning, car fumes and firecracker smoke become trapped above the city.

“Incidents of stubble burning are decreasing, but…smoke created by firecrackers needs to be controlled,” Delhi Environment Minister Gopal Rai told news agency ANI.