Firecrackers will be allowed between 11:55 pm and 12:30 am on Christmas and New Year, said Judges AK Sikri and Ashok Bhushan.

In Delhi, crackers will be allowed only in designated spots, which need to be identified within a week.

Only crackers that are within noise pollution limits set in an earlier verdict will be allowed. The "ladi" or chain firecrackers - a Diwali favourite - are banned.

Only licensed traders can sell firecrackers, which are to have less lithium, barium and arsenic - chemicals that cause breathing difficulties and cancer.

Crackers cannot be sold online and if they are, such e-commerce sites will be hauled up for contempt. The court referred to Flipkart and Amazon.

The police officer in charge of an area will be responsible for any violation of the new rules. For now, no cracker complies with the court's description.

On October 9 last year, the court had temporarily banned the sale of firecrackers before Diwali. The ban was an experiment to see the impact on pollution, the judges had said.

In hearings, the court had noted that Article 21 of the constitution on the Right to Life - a plea used by the petitioners - applied to all, including cracker-makers.

Each year, smoke from firecrackers covers Delhi and its neighbourhood in a haze that can linger for days as wind speeds drop in the cooler weather, adding to pollution caused by the burning of crop residue, vehicle exhausts and industrial gases. Last year, chief minister Arvind Kejriwal called the city a "gas chamber."