People in Mumbai thronged markets to buy decorative items and jewellery ahead of Diwali on Friday

Starting from Dhanteras today, the festivals of Roopchaturdashi tomorrow, Diwali on 12th November, Govardhan Puja and Annakut on 13th November and Bhaiya Dooj on 15th November will be celebrated. According to an estimate by the Confederation of All India Traders (CAIT), today there was a trade worth more than Rs 50,000 crore across the country

Diwali is the festival of lights. It symbolises the spiritual "victory of light over darkness, good over evil, and knowledge over ignorance". Diwali is observed on Amavasya (or the new moon), the 15th day of the month of Kartik, every year.

Meanwhile, the Bombay High Court on Friday modified its earlier order and said firecrackers can be burst only between 8 pm and 10 pm during Diwali in view of the air pollution situation.

A division bench of Chief Justice D K Upadhyaya and Justice G S Kulkarni had on November 6 permitted the bursting of firecrackers for three hours, between 7 pm and 10 pm, within the limits of all municipal authorities in Maharashtra.

During a hearing on Friday, the bench noted that Mumbai was witnessing a decline in the bursting of firecrackers. "Let's not become Delhi. Let's remain Mumbaikars," chief justice Upadhyaya said.

The bench said there are some critical areas of the city where the air quality index (AQI) remains poor. "We are in an emergent and drastic situation. A lot of efforts have been taken, but maybe something more needs to be done," the court said.

The bench said it was modifying its order of November 6. "The time to burst crackers shall be limited from 8 pm to 10 pm," it said. Considering the prevalent situation, it does not deem it appropriate to modify another direction in its November 6 order which had banned the entry of vehicles transporting debris in the city but permitted vehicles carrying construction materials to ply if they were fully covered, the bench said.

"All other directions of the November 6 order shall continue to operate till November 19," it said. After November 19, concerned municipal corporations shall decide whether vehicles carrying debris should be allowed after considering the AQI, the court said.

The source of pollution also needs to be ascertained, it said, while emphasising the need for a study by experts to understand the causes. "Is there any study as to what is the nature of this pollution...is it only dust or is there any chemical component in it? Because we are seeing many hospitals flooded with patients with respiratory illness," the court said.

The court was hearing a bunch of petitions including one taken up by it on its own ('suo motu') concerning the rising air pollution in Mumbai. The court will hear the matter further on December 11. During the hearing, it noted that the problem of air pollution would recur.

"What needs to be done is a study by experts to go into causes and also measures to mitigate the pollution. We are not experts," it said, adding that a constant monitoring mechanism was also needed.