India's Supreme Court has banned the sale of fireworks in New Delhi and nearby towns, 10 days before the Hindu festival of Diwali, in a move to curb the capital's deadly air pollution.

The ban is effective immediately and lasts until November 1.

Millions of highly-polluting fireworks are lit on Diwali, which falls on October 19 this year.

The court said on Monday that it would assess whether banning fireworks will make a difference to New Delhi's air, which is among the dirtiest in the world.

The court said that people who had already bought fireworks could use them, but that new ones could not be sold.

Activists fear people will smuggle fireworks from neighbouring states.