At least 17 people, including 10 children, were killed after an explosion at a fireworks factory at Deeg, about 30km from Bharatpur (Rajasthan), police said on Thursday.
Another 18 people were hurt after the explosion.
"At least 17 people died after a blast brought down houses in and around a fireworks factory," Jagdish, a police officer who goes by one name, told Reuters by telephone from Jaipur.
The explosion came only days before the Indian holiday of Diwali, when millions of Indians take to the streets to let off fireworks in one of the biggest festivals of the year.
Poor children often clandestinely work at makeshift fireworks factories in India, which are often in people's homes, and almost every year there are fatal accidents.