What aarti literally involves
Aarti is the ritual of waving a lit lamp — traditionally a five-wick brass lamp fed with ghee or camphor — in a circular motion before an image or deity, usually accompanied by a devotional song describing the deity's glory. The word itself is thought to derive from the Sanskrit "aratrika," referring to something that removes darkness (the root "ratri" meaning night). It's typically the closing act of a longer puja, though it's also performed on its own, especially at the end of the day.
Why fire specifically
Of the five elements traditionally offered during a full puja — earth (flowers), water, fire, air (incense) and space (sound, via a bell or conch) — fire is treated as uniquely purifying and revealing. The circling flame is meant to illuminate the deity's form for the assembled devotees, echoing a time before electric light when a lamp was literally the only way to see the image clearly in a dim temple sanctum. Many devotees also pass their hands briefly over the flame afterward and touch them to their own eyes or forehead, carrying a portion of that light back to themselves.
The order of the circling
Traditionally the lamp is circled a set number of times at different parts of the deity's form — commonly the feet, then the navel, then the face, and then the whole body — rather than moved randomly. Some traditions circle four times at the feet, two at the navel, one at the face, and then seven full circles of the whole figure, though local and family variations are common.
Why it's sung, not silent
Aarti is almost always accompanied by a specific devotional song written for the occasion — Om Jai Jagdish Hare for Vishnu-related worship, or a specific aarti for the deity being honoured, such as the Hanuman Aarti or Ganesh Aarti. The singing is meant to be participatory — a bell is rung, sometimes a conch is blown, and the household or congregation joins in rather than watching a single person perform a silent gesture. This is part of why aarti, more than most other rituals, tends to be the moment when even less ritually observant family members join in.
When it's performed
Beyond its place at the close of a formal puja, aarti has its own fixed daily and weekly moments: most temples perform it at sunrise, midday and sunset (sandhya aarti), and many households perform a short evening aarti even on days without a full puja. It also marks the close of a festival day or a specific vrat, and a distinct form — Ganga Aarti — is performed as a major public event on riverbanks such as Haridwar and Varanasi. If you're building a daily practice of your own, see our guide on how to start a daily prayer routine.