Many residents of New Delhi defied a firecracker ban on Diwali on Monday as political parties traded blame on who was responsible for the Indian capital’s foul air.

The air quality index across various hotspots of the city of about 20 million breached the “hazardous” category late in the day, with a peak of 768 in the Jahangirpuri area - more than 15 times the “good” level.

Delhi Chief Minister Arvind Kejriwal’s government said last week that people who let off firecrackers during Diwali would face up to six months in jail, under a broader ban introduced to help combat extreme winter pollution.

Firecrackers have for generations been an integral part of Diwali, the Hindu festival of lights, which takes place next week throughout India.

But city authorities have banned their sale and use over the festival period for the past two years, along with other measures including controlling waste burning, and the use of anti-smog guns and water sprinklers.

Environment Minister Gopal Rai told reporters that people caught setting off firecrackers this time would face a fine of 200 Indian rupees ($2.41) and jail term of up to six months.

Those found storing and selling firecrackers would face fines of 5,000 rupees and up to three years in jail.

A broader ban on setting off firecrackers was imposed last month and will run until Jan 1.

Diwali usually also coincides with a rise in emissions from crop stubble burning in neighbouring states, which increases the concentration of fine particles in the air to several times above the safe limit set by the World Health Organization.

Some Hindus see the Diwali firecracker ban as an attempt to interfere with observance of their religion.