Clay vs Plaster Of Paris Ganesha Idols: What's The Environmental Difference?

Add as a preferred source on Google

For ten days, the idol sitting in your living room looks much the same whether it's made of clay or Plaster of Paris. It's only after visarjan, when the idol goes into a river, lake, or the sea, that the real difference between the two materials shows up - and by then, it's too late to change your mind.

Photo Credit: Chat GPT

Here's what separates the two, and why environmental authorities across several states have spent years trying to phase one of them out.

The Core Difference: What Each Material Is Made Of

Clay idols, traditionally called shaadu maati in Maharashtra, are made from natural, unprocessed clay sourced from riverbeds. Plaster of Paris, or PoP, is a manufactured material made from calcium sulphate hemihydrate, essentially gypsum that's been heated and ground into a fine powder, then mixed with water to set into a hard, mouldable form.

Clay is the older tradition. PoP became popular later because it's cheaper, lighter, easier to mould into intricate shapes, and lets artisans produce larger idols at a lower cost.

How Each One Behaves In Water

This is where the two materials genuinely part ways. Clay dissolves in water in roughly an hour, breaking down into natural sediment that water bodies can absorb without much disruption. Plaster of Paris behaves almost the opposite way: it doesn't dissolve so much as it disintegrates slowly, sitting at the bottom of lakes and rivers for months, sometimes longer, before it breaks down.

A 2014 study of two Mumbai lakes found that hardness, chlorinity, salinity, and turbidity levels all changed measurably after PoP idols were immersed. Researchers studying Mumbai's Gorai creek in 2019 documented similar water-quality shifts tied to idol immersion.

It's Not Just The Material, It's What's Painted On It

The idol itself is only part of the problem. PoP idols are typically finished with synthetic, oil-based paints that often contain heavy metals like lead, mercury, and cadmium. When these idols sit in water for months breaking down, those chemicals leach out gradually, harming aquatic life and altering local ecosystems in the process. Clay idols are far more compatible with natural, water-based or vegetable-dye paints, which don't carry the same toxic load.

Why PoP Still Dominates The Market

If clay is so much better for water bodies, why hasn't it taken over? The answer is largely economic. PoP is cheaper to source, easier to mould into detailed, lightweight idols, and far more forgiving for artisans working at scale. Clay idols, by contrast, are heavier, more prone to cracking during production, and usually have to be made smaller as a result; all of which pushes up their price. One Mumbai-based artisan who switched entirely to clay idols has spoken about earning a fraction of the profit he'd make on PoP, simply because clay is costlier to work with and harder to sell at volume.

The Regulatory Push Toward Clay

Several states have moved to restrict PoP idols directly. Maharashtra's High Court has ordered a ban on Plaster of Paris idols over the environmental damage caused by their immersion, and Goa's State Pollution Control Board has issued fresh 2026 directions regulating and restricting PoP idols ahead of this year's festival. Enforcement, though, remains inconsistent - PoP idols are still commonly sold and immersed in many cities despite the rules on paper.

Some cities have also seen a genuine shift in habits: Bengaluru's civic body recorded far more clay idol immersions than PoP ones in recent years, alongside a rise in idols immersed at home rather than in public water bodies, which is itself part of the broader eco-friendly push.

What You Can Do

If you're buying an idol this year, a few small choices make a real difference:

• Choose a clay idol over a PoP one wherever it's available
• Ask for water-based or natural paints, especially if you're buying a bigger idol
• Immerse the idol in a bucket or tank at home instead of a natural water body when possible
• Consider a symbolic immersion with a reusable brass or stone idol, especially for larger community celebrations