THE CROAK is a weekly environmental newsletter put out by the eCoexist team. It is the voice of the environment on its last legs, the final croak that can either be a plea for attention or a call of triumph as the frogs jump out of the well of ignorance and denial.

Punaravartan: Transformation renewal and restoration

In May 2020,  the Government of India, through the Central Pollution Control Board banned the use of Plaster of Paris and chemical paints , to make religious idols meant for immersion. This is a landmark decision that will ensure that our rivers, lakes and all water bodies stay free of any non biodegradable man made objects.

The immediate material to replace Plaster of Paris would be natural clay , shaadu maati - as it is known in Maharashtra. However, natural clay is a mineral resource - i.e. it is mined from the ground and therefore in limited supply. The mines where this clay comes from create an ecological disaster in the region of another scale. 

While the switch to natural clay is a good beginning, eventually if the entire festival turns to using natural clay it will not be a sustainable solution for the future. 

Is it possible to recycle the clay used for idols and create a closed loop?


Bentonite clay mines in Gujarat Source : Gujarat Mineral Development Corporation Ltd

Bentonite clay mines in Gujarat 

Source: Gujarat Mineral Development Corporation Ltd

Read the full document of the Revised Guidelines here
About Natural clay

Ball clay is an extremely rare mineral found in very few places around the world. Its name dates back to the early methods of mining when specialized hand tools were used to extract the clay in rough cube shapes of about 30 cm. As the corners were knocked through handling and storage these cubes became rounded and ball shaped. It also is sometimes referred to as plastic clay.

Ball clay consist of ultra fine clay particles. This helps to make them sticky (or 'plastic') and easily shaped when damp (the word 'clay' is derived from the Old English 'claeg', meaning sticky). Some also have fluid properties that are valuable in the casting of large ceramic pieces such as toilet bowls. Ball Clay is a variety of Kaolinite, like china-clay. It differs from china-clay in having high plasticity.

(Source: Gujarat Mineral Development Corporation Ltd)

Reusing and Recycling Natural Clay

To reduce the amount of clay that is mined from Nature it is possible to explore the recycling of clay sludge after the immersion ritual. When immersed in natural water bodies, this clay tends to form an impermeable sediment at the bottm of the lake or river and affect the ecosystems. When we do a home immersion the clay can be put into gardens and pots , but requires to be mixed with red earth for plants to grow in it.

For 2021, the eCoexist team decided to experiment with the recycling of damaged clay idols left over with us. 

We learnt of the process of 'slaking' which is normally used by sculptors and ceramic artists when handling clay. Slaking refers to the manner in which dry clay breaks down when immersed in or exposed to water. 

Typically the water attacks the surface and particles simply fall away. When slaking is complete a pile of fine material will be found settled on the bottom of the container of water, power mixing will then produce a slurry. Clays that slake well will break down in minutes if chunks are less than about 1 cm in size and all have exposure to the water. Very plastic clays may not slake since the wetting of the surface will cause swelling and act as a barrier to further water penetration.

Source :

Procedure to recycle

Click on picture to watch a video of the recycling process

A very simple manual procedure was tested out with fair results. This involved

1. Immersion of clay idol

2. Drying of sludge

3. Powdering 

4. Sieving 

The powder so obtained was then sent to several ceramic artists and sculptors to test by making new idols . A small portion of fresh clay was added to some mixes and others were made entirely of the recycled powder. The resultant clay idols were as good as new. The procedure involved minimal quantitative loss of clay. 

Circular Economy for clay?

Is this a solution that could be scaled up to make an impact on the mining of ball clay ? What would it entail to create a circular economy around this one material and product? 

The first step in closing the loop is to ensure that the sludge from the old clay is recollected after visarjan - this will involve some cooperation on part of the devotees. It will also require a collection system to be established for the city.

Recycling also involves costs of collection, transportation and storage and a cost benefit analysis needs to be done to check if the short term costs of recycling balance out the fresh mining of clay. In the long term of course, recycling of minerals is surely a more sustainable option. 

In terms of quality, it appears that slaking renders the clay finer and therefore improves on the quality of the recycled product, however we need to check for how many cycles this holds true until new clay needs to be added to ensure the same quality. 

The use of paints on the clay idols will also affect the quality of recycled powders, as the particles of paints will be mixed into the sludge and will be hard to seperate from the recycled powder. 

Keeping rivers clean

Ideally no man made substance should be allowed to be put into natural water bodies which are living habitats and eco systems.

The revised guidelines of CPCB also advise about treatment of water after immersion as well the need for desludging ... 

Lime or alum or any other equivalent coagulant should be added in designated temporary lined pond/tank as pre-treatment option for ensuring settling of solids. After completion of immersion, only supernatant water may be allowed to flow into river/pond/lake, as the case may be, after checking for colour and turbidity as per BIS specification for Drinking Water IS 10500:2012. 

Post immersion, with remains of idols and activities such as desludging of the designated area should be undertaken and ensured its disposal as per Solid Waste Management Rules 2016 as amended thereafter, within 24 hours by the concerned ULBs, as per these guidelines.

What is to be done with this sludge? If appropriately harvested treated and recycled natural clay sludge can conserve our clay resources while ensuring our water bodies stay clean.

Implementing the CPCB guidelines

The revisions to the Guidelines for Immersion are a welcome step forward into making the festival of Ganesh Chaturthi totally ecofriendly... and we can do more - click on the link below to see how we can take this further ...

Read our review of the Revised Guidelines here
What you can do ...

1. Choose to use an idol made of recycled clay

2. Conduct a home immersion

3. Collect the clay sludge after the visarjan 

4. Deposit it with us to help close the loop and promote a circular economy

For 2021, eCoexist will be collaborating with Swach Coop members to recieve clay for recycling from devotees. Please contact us at [email protected] to know more . 

GP8:Eco Ganesh Idol: Punaravartan Mysuri  - 11"
GP8:Eco Ganesh Idol: Punaravartan Mysuri - 11"
eCoexist renews clay used in last years idols to make a new series called Punaravartan – which means renewal. Made by the sculptors of Pune, this series is an effort to encourage…
View product
GP9:Eco Ganesh Idol: Punaravartan Dagdu - 9"
GP9:Eco Ganesh Idol: Punaravartan Dagdu - 9"
eCoexist renews clay used in last years idols to make a new series called Punaravartan – which means renewal. Made by the sculptors of Pune, this series is an effort to…
View product


Did you enjoy this newsletter? Subscribe on our website

The Croak is a weekly environmental newsletter put out by the eCoexist team. It is the voice of the environment on its last legs, the final croak that can either be a plea for attention or a call of triumph as the frogs jump out of the well of ignorance and denial. Satirical, urgent and wise the newsletter brings to your attention, topics of global environmental relevance as well as emerging encouraging alternatives. Put together by a team of passionate Nature lovers, The Croak hopes to look at the environmental crisis in its face. It is a tool to reconnect readers to Nature, through questioning and self reflection. To understand the outer environment as a reflection of our own inner state, individually and as a species. And to take responsibility for enabling change.
If you would like to contribute articles on ecology consciousness and sustainability please get in touch with us.

Donate Here! Use the Gpay code on the right to send us a donation today. The eCoexist Foundation is a not for profit Section 25 company registered in Pune.
Please send us an email with your details at [email protected] once you have made the payment so we can send you a receipt. Currently we take donations from India only. We thank you sincerely!
Facebook Twitter Youtube Instagram
306 Harmony Wing 2 North Avenue Kalyaninagar Pune 411006
All rights reserved.

Not interested in our newsletter anymore? Give us feedback before you unsubscribe.