Homes and temples glow across India as Diwali celebrations begin

Diwali is a major festival rooted in Hindu traditions and widely celebrated across India. It is known as the festival of lights because people illuminate homes, temples, offices and streets. The lights symbolise the triumph of light over darkness and good over evil. The festival falls on the darkest night of Kartik, a Hindu lunar month.

Families prepare by cleaning and decorating their homes. They place traditional oil lamps called diyas around entrances and create colourful rangoli patterns. People also pray, share sweets, exchange gifts and gather for festive meals. On the main evening, many families offer prayers to Lakshmi, the goddess of wealth and prosperity.

Diwali matters because it combines religious meaning with community celebration. It commemorates Lord Ram's return to Ayodhya after defeating Ravan in the Ramayana. Its lights, prayers and gatherings bring together families and communities, although traditions differ across regions and religions.

Diwali is a nationwide celebration involving millions across India. It reaches homes, temples, offices, streets, markets and financial institutions. The festival is not limited to one region or one community. Its traditions vary, but lighting, prayer, family gatherings, sweets and gifts give the celebration a shared character.

The festival also travels with Indian communities around the world. Families and friends abroad come together for festive gatherings and exchange gifts, just as celebrants do in India. In India, markets become busy with shoppers buying festive essentials beneath bright decorations. Stock exchanges also hold a special one-hour session called Muhurat trading because many investors consider Diwali purchases auspicious.

Diwali's scale matters because it combines a large public celebration with personal and religious observances. The article does not give a worldwide population figure, but it describes millions celebrating in India and communities participating internationally. Its reach extends across faiths, including Hindus, Sikhs, Jains and others.

The five-day festival begins with Dhanteras, when buying gold, silver or new utensils is considered auspicious. Chhoti Diwali follows with oil lamps and, in some homes, firecrackers. The third day is the main celebration, featuring evening prayers to Lakshmi, festive meals and fireworks. The fourth varies, while Bhai Dooj celebrates brothers and sisters.

Regional customs shape the fourth day. Some communities hold family gatherings and New Year festivities. Across the days, families clean and decorate homes, make rangoli, exchange sweets and gifts, and gather for prayers and feasts. Markets fill with shoppers and colourful decorations. Fireworks are common, but their use differs among households and communities.

Religious observances also differ. Sikhs mark Bandi Chhor Divas, commemorating Guru Hargobind's release from imprisonment. Jains observe Mahavira's attainment of moksha. These traditions show why Diwali is broader than a single ritual or faith, even though it is rooted in Hindu traditions.

Firecrackers can cause pollution to rise because they add emissions directly to the air during a concentrated period of celebration. Diwali fireworks are set off by households and communities, often alongside other pollution sources. The article warns that this extra pollution can worsen already deteriorating air quality, particularly in northern India.

Seasonal weather conditions and the burning of crop residue are already contributing to poor air quality. When fireworks are added, the total pollution burden increases. Delhi's AQI reached 391, in the very poor category, before the festival. Mumbai's AQI had recently reached 322, although it later improved to 104, in the moderate category.

The concern is that fireworks could trigger another sharp increase after conditions improve. Delhi authorities fear pollution levels may rise further following celebrations. Mumbai faces a similar risk. The issue has prompted restrictions and debate over certified green firecrackers, while critics question whether conventional fireworks can be kept out.

Green firecrackers are certified fireworks designed to produce 20–30% less emissions than conventional fireworks. They are intended to let people continue some Diwali celebrations while reducing the pollution released into the air. Their role matters because Delhi already had very poor air quality before the festival.

On Monday, India's Supreme Court permitted the manufacture, sale and use of certified green firecrackers in Delhi and surrounding areas. The permission applies for a limited period. This approach tries to control both the type of fireworks available and the time when they may be used, rather than allowing unrestricted conventional fireworks.

The policy remains contested. Critics question how effective green firecrackers are at reducing overall pollution. They also fear conventional products could enter Delhi from neighbouring states. If that happens, the intended emissions reduction may be weakened. Pollution could still rise after celebrations, especially because weather and crop burning are already harming air quality.

For Hindus, Diwali celebrates Lord Ram's return to Ayodhya after his victory over Ravan, the main antagonist in the Ramayana. This story gives the festival its broader meaning: the triumph of good over evil. The lights and prayers express that spiritual theme.

Sikhs mark Bandi Chhor Divas, or Prisoner Release Day, during the Diwali period. It commemorates the release of their sixth guru, Guru Hargobind, from imprisonment at Gwalior Fort in the early 17th Century. This is a distinct Sikh religious observance associated with the season.

For Jains, Diwali marks Lord Mahavira's attainment of moksha, or liberation from the cycle of rebirth. Mahavira was the 24th and last Tirthankara, or spiritual teacher, of the current era. These stories show that the festival has different meanings among communities, while people across faiths may still join its wider celebrations.

The air quality index, or AQI, is a numerical scale used to describe how polluted the air is. Higher readings indicate worse air quality, while categories help communicate the severity. In the article, Delhi's reading of 391 was classified as very poor. Mumbai's reading of 104 was described as moderate.

Pollution can build when seasonal weather conditions contribute to deteriorating air quality. Burning crop residue adds another source of emissions, especially in northern India. These factors create poor conditions before Diwali fireworks begin. Firecrackers then release additional emissions over a short period, increasing concern that readings will rise sharply.

The article illustrates this pattern with two cities. Delhi was already at 391 before the festival, prompting fears of a further increase. Mumbai improved from 322 on 24 October to 104 on Friday, but officials still feared fireworks could cause another spike. The AQI makes these changes visible and easier to compare.