At Joy Durga Bhandar, a workshop in north Kolkata's Kumartuli, Koushik Ghosh begins an idol with a framework of bamboo and wood tied together with jute rope. From this base come the sculpted figures, decorations and layers of colour that devotees see during Durga Puja.

Koushik knows this process well. For generations, artisans in Kumartuli have worked with bamboo, straw and clay, shaping idols by hand for Kolkata's Durga Puja celebrations.

Over time, many workshops also adopted thermocol decorations, synthetic paints and plastic ornaments because they were quicker or cheaper to use.

Koushik is looking for ways to bring more traditional materials back into his work.

"The frame, the clay, the straw, those were always ours. The thermocol and the chemical colours came later, because they were cheaper and faster. I am going back to what was here before," he says.

He is working towards idols decorated with natural clay, shola (the soft pith of a plant used for delicate ornaments) and natural colours instead of thermocol.

Every year, after Durga Puja, thousands of idols are immersed in the Hooghly River and other water bodies. In 2025, around 5,200 idols were immersed across 34 major Hooghly ghats and approximately 30 other water bodies in Kolkata and nearby suburbs, according to The Times of India.

Civic workers clear debris from immersion sites, but thermocol and plastic decorations need careful collection and disposal because they can persist in the environment.

Neel, a volunteer who has spent several seasons cleaning the Hooghly's banks near Babughat, remembers finding thermocol floating on the surface, coloured residue near the banks, and plastic decorations gathering along the ghats.

For Koushik, the challenge is to make the decorations less wasteful while keeping the craft affordable for the families who depend on it.

From bamboo frames to Durga's eyes: Inside the craft of Kumartuli

Walking through Kumartuli's narrow lanes, the smell of wet clay is difficult to miss.

The neighbourhood, whose name comes from kumor (potter) and tuli (neighbourhood quarter), has been home to idol makers for more than three centuries. Its workshops stand between Rabindra Sarani and the Hooghly, the river that has long supplied the fine alluvial soil used in their craft.

Traditionally known as Ganga maati, this clay is softer and finer than ordinary earth, allowing artisans to sculpt delicate features.

At Koushik's workshop, everything begins with the kathamo (a framework made from bamboo and wood).

"The frame is not just engineering," he explains. "It is the first thing she stands on."

The structure must support the central Durga figure, accompanying figures, a lion and other sculpted elements.

Next comes khar bandha (tying straw around the frame). Carefully shaped bundles of straw form the arms, waist, chest and other features. If the straw is tied incorrectly, the figure may lose its balance or the clay may crack.

The first clay layer is entel mati (sticky clay mixed with tush, or rice husk). It takes about three to four days to dry.

Artisans then apply bele mati (finer, smoother clay), allowing another five or six days for drying, depending on the weather. Any cracks are repaired with fresh mud.

Faces, hands and other delicate parts are often made separately........

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