Pooja lamps are filled with ghee or with oils such as sesame (gingelly) oil, and the choice follows tradition. A ghee diya needs only a clean lamp, a cotton wick and a safe place to burn, and the studies we found show it still gives off smoke, like any flame.
We describe traditions as our sources do, and make no claim about what a lamp does spiritually; that belongs to your family, your priest and your elders.
At a glance
- Ghee and sesame (gingelly) oil are both recorded as pooja lamp fuels: a museum record describes aarti lamp wicks soaked in ghee, and a Chennai temple filled over 30,000 lamps with gingelly oil in 2024.
- A ghee diya needs a clean, dry lamp, a cotton wick soaked in melted ghee, a stable heat-resistant surface, and someone watching it.
- In a small chamber test, a ghee lamp gave off the same particles as a peanut oil lamp and about 16 per cent less carbon monoxide; no study has measured a ghee diya in a home.
- No published burn time exists for a set amount of ghee; time your own lamp with a level teaspoon.
- Fire services say never to leave a diya burning unattended, to keep 10 cm between lamps, to put them out before bed, and to use LED lights for decoration.
Why are ghee and sesame oil used in pooja lamps?
Because the traditions call for them, not because a test picked them. A museum record describes a South Indian aarti lamp whose wicks are soaked in ghee or camphor. At one Chennai temple in 2024, volunteers filled more than 30,000 lamps with gingelly oil for Karthigai Deepam. The fuel varies with the tradition and the occasion.
The museum record, from Singapore's National Heritage Board, is for a 19th-century bronze lamp. The gingelly oil detail comes from a neighbourhood newspaper's report on the Deepotsavam at Sri Vedantha Desikar Temple, Mylapore.
Researchers at Dev Sanskriti Vishwavidyalaya in Haridwar write that cow ghee "is given more importance" for lighting lamps in Indian temples. They add that religious texts name different oils for different worship, such as mustard oil for Saturn.
Both are old lamp fuels. A 2017 analysis of eight lamps from the 6th to 8th centuries AD, excavated at Astana in north-west China, found ruminant fat, cattle ghee and sesame oil among the fuels.
Does the ghee for a diya need to be food-grade cow ghee?
No rule we could find requires it. One research group says Indian temples give cow ghee more importance for lamps, but we found no standard, and no reading of scripture we could check, that sets a food grade for lamp fuel. The practical case for food-grade ghee is simple: one jar can serve the kitchen and the altar.
If you buy a product sold only for lamps and its label says it is not for eating, keep it out of the kitchen. If you buy food ghee, our article on what ghee is adulterated with in India and how labs catch it explains what a laboratory report can show. Every jar of Himdhara ghee carries a batch code, and the report for each batch is published before the batch ships.
How do you set up a ghee diya?
Use a clean, dry diya, a cotton wick and ghee soft enough to spoon. Put the lamp on a stable, heat-resistant surface before you light it, keep it away from anything that can catch fire, and stay with it while it burns.
- Choose the spot first. Greater Manchester Fire and Rescue Service's candle safety advice asks for a flat, heat-resistant surface such as a ceramic tile or metal plate, and not under shelves. London Fire Brigade adds: away from curtains, papers, furniture and clothes, and out of reach of children and pets.
- Prepare a cotton wick. Two of the studies below used cotton or muslin wicks, and the museum record describes wicks soaked in ghee. Soak yours in melted ghee first.
- Fill with a dry spoon. A wet spoon in the jar invites spoilage, as our guide to storing ghee and its shelf life explains.
- Space a row of lamps. Greater Manchester's fire service asks for at least 10 cm between lit candles; we use the same gap for diyas.
- Do not move it once lit, and do not lean over the flame, as the same service advises for candles.
- Put it out before the ghee runs out. The fire service warns that a candle burnt all the way down can crack its holder, and that an oil burner should never boil dry.
How long does a ghee diya burn?
We cannot give a reliable figure. We found no published measurement of how long a set amount of ghee lasts in a diya. It will depend on the wick, how far it stands out of the ghee, the shape of the lamp and any draught. The honest method is to time your own lamp once and note the result.
The studies we read burned lamps for fixed periods to collect smoke, ten minutes in one and about 20 to 30 minutes in another, so neither gives a burn time. To measure your own, put a level teaspoon of ghee in your usual diya with your usual wick, note when you light it, and stay with it until it goes out.
London Fire Brigade advises putting diya lamps out when you leave the room and before bed. If your practice keeps a lamp lit continuously, someone should be awake and watching it.
What does burning ghee release indoors?
Smoke particles, carbon dioxide and some carbon monoxide, as any flame does. The closest study we found, a small chamber test, measured no difference in particles between ghee and peanut oil lamps, and somewhat less carbon monoxide from ghee. We found no study that measured a ghee diya in an ordinary room at home.
That test, by Shukla and colleagues at Dev Sanskriti Vishwavidyalaya, appeared in 2022 in a peer-reviewed journal the university publishes. They burned Sahiwal cow ghee and refined peanut oil in a metal lamp with a muslin wick, each for ten minutes inside a closed 3 × 2 × 2-foot cabinet with an indoor air-quality monitor. Particles (PM1, PM2.5, PM10), nitrogen dioxide, sulphur dioxide, ozone and carbon dioxide did not differ significantly. Carbon monoxide was 15.93 per cent lower with ghee. The results cannot be read as room concentrations. The authors take this as support for ritual use of ghee; we would not go that far on one small test of one lamp.
Two other studies add a little. A 2022 study in Environmental Science & Technology burned nine household fuels used in Tibet. Yak dung and powdery incense gave off large amounts of carbon monoxide and aerosols; wood, coal, a ghee lamp, stick incense and diesel gave off "abundant CO2 but fewer aerosols" from flaming combustion. A 2025 laboratory analysis in Shukla's journal, led from SVNIT Surat, collected soot from diyas burning seven fuels. Kerosene soot showed the strongest signals linked to condensed aromatic compounds, ghee soot weaker ones. It analysed the soot's make-up, not how much reached a room.
| Fuel | Where we found it recorded | What the tests we read found |
|---|---|---|
| Ghee | Aarti lamp wicks soaked in ghee (museum record); given "more importance" in temple lamps (Shukla 2022) | Particles as peanut oil, carbon monoxide 15.93 per cent lower (chamber test); fewer aerosols than yak dung (Tibet study); weaker soot aromatic signal than kerosene (2025) |
| Sesame (gingelly) oil | Temple lamps for Karthigai Deepam, Chennai, 2024; residues in 6th–8th century lamps from Astana | No emissions test found |
| Peanut oil | Commonly used for lamps in India (Shukla 2022) | The comparison fuel in the chamber test |
| Mustard oil | Named in texts for the worship of Saturn (Shukla 2022) | One of the seven fuels in the 2025 soot study |
| Camphor | Aarti lamp wicks (museum record) | No emissions test found |
| Kerosene | Not described as a pooja fuel in the sources we read | Strongest aromatic signal in soot (2025 lab study) |
None of these studies shows that a ghee lamp is safe to breathe or healthier than another; they measured smoke, not people. If anyone at home has asthma or another lung or heart condition, follow their doctor's advice on lamps and incense.
How do you keep a diya safe indoors?
Treat a diya as an open flame. London Fire Brigade names diya lamps directly: never leave them unattended, put them out when you leave the room and especially before bed, and keep them in heat-resistant holders on a stable surface, away from curtains, papers, furniture and clothes, and out of reach of children and pets.
- Fit smoke alarms. Greater Manchester advises a working alarm on each level of the home, tested at least monthly.
- Mind decorations. Warwickshire Fire and Rescue Service's Diwali fire safety advice says to keep diyas away from low-hanging decorations and fabrics, in non-combustible containers or on stable surfaces so they cannot tip.
- Use electric lights for decoration where you can. Both London and Warwickshire suggest LED or battery lights as a safer alternative to open flames.
- Do not light lamps when drowsy, or after alcohol, drugs or medication, as Greater Manchester advises for candles.
None of the candle pages we read gives a ventilation rule for lamps. Greater Manchester's advice on ceremonial burning says to burn incense with windows or doors open, so smoke and carbon monoxide do not build up, and its candle page says to keep flames out of draughts. So air the room, but keep the diya out of the draught.
Can you burn old or rancid ghee in a diya?
If ghee has gone rancid, do not eat it. Burning it in a lamp avoids waste, but we found no test of how rancid ghee burns, so we cannot say whether it smokes more. Ghee with mould, or with water in it, is a different matter: we would throw it out.
Our storage guide lists the signs that ghee has turned, such as a sour or stale smell and a bitter taste. Mark any jar set aside for lamps so it does not drift back into cooking, and never pour ghee left in a diya back into the kitchen jar.
The short version
Ghee and sesame (gingelly) oil are both recorded as pooja lamp fuels, and the choice is a matter of your own tradition. Nothing we found requires food-grade ghee, and we found no measured burn time, so time your own lamp. A small chamber test found ghee and peanut oil lamps gave off the same particles, with less carbon monoxide from ghee; no study we found measured a ghee lamp in a home. Never leave a diya burning unattended, keep it away from anything that can catch fire, and air the room.
Sources
Further reading behind the figures above. Himdhara's own numbers — yields, batch results — come from our production records and the batch reports on the lab reports page.
- Shukla D, Sursaut RM, Kumar M (2022). Reduced Carbon Monoxide Emission in Ghee Lamp than Peanut Oil Lamp. Interdisciplinary Journal of Yagya Research.
- Zhang X, Xu J, Zhai L, Zhao W (2022). Characterization of Aerosol Properties from the Burning Emissions of Typical Residential Fuels on the Tibetan Plateau. Environmental Science & Technology.
- Jangir R, Rathore K, Kumar K, Kumar D (2025). Comparative Physicochemical Characterization of Particulate Matter Emitted from Diya. Interdisciplinary Journal of Yagya Research.
- London Fire Brigade (n.d.). Candles. London Fire Brigade, fire safety at home.
- National Heritage Board, Singapore (n.d.). Lamp (Asian Civilisations Museum, 1998-01084). Roots.sg.