As millions across India illuminate their homes, temples, offices, and streets in celebration of the Hindu festival of lights known as Diwali, growing concerns over air pollution threaten to overshadow the festivities. Observed on the darkest night of the lunar month of Kartik when the moon is not visible, Diwali symbolizes the triumph of light over darkness and marks the return of Lord Ram to Ayodhya after his victory over Ravan. The celebrations, which vary across India's regions and communities, traditionally involve prayers, family gatherings, the exchange of sweets, and firecrackers. However, the burning of crop residue and fireworks during Diwali have contributed to deteriorating air quality in northern India, with Delhi experiencing hazardous pollution levels this year. In an attempt to limit pollution, India's Supreme Court has permitted the manufacture, sale, and use of certified "green" firecrackers in Delhi and surrounding areas for a limited period. Despite these measures, critics question their effectiveness, and concerns remain that conventional firecrackers could still make their way into the capital from neighboring states. While Diwali is often associated with fireworks, it is about much more than that: families clean and decorate their homes, gather for elaborate feasts and gift exchanges, create colorful rangoli patterns at entrances, and shop for festive essentials beneath brightly lit decorations. As Indian communities spread across the globe, Diwali is also celebrated internationally as an auspicious time to make new purchases and strengthen family bonds. With Diwali falling on November 8 this year, India's stock exchanges will hold a special one-hour trading session known as Muhurat trading for investors who believe buying and selling shares on the festival is favorable. Although rooted in Hindu traditions, Diwali is celebrated by people across different faiths and communities worldwide.