Ganesh Chaturthi was once a more private festival. There was a rise in its popularity from the time of the warrior king Shivaji up to the ascendancy of the British Raj, but it was usually celebrated at a more intimate family level. But thanks largely (or wholly, according to some) to the freedom fighter Bal Gangadhar ‘Lokmanya’ Tilak, who saw it was a way or circumventing British rules about public gatherings, it became a much more public community event.

Today, it is a festival on a grand scale, particularly in western India, and to some extent in the south, and increasingly celebrated in other parts of the country as well. The god is known by several names — Ganpati, Ganesh, Ganesha, Vinayaka, Binayak — and one whose worshippers cross caste divides.

But one part of the festival’s rituals, as practised in modern India, has those of a greener mindset worried about environmental impact: the immersion.

Unlike in olden times when idols were made of clay, today’s Ganeshas are usually gypsum plaster, calcinated hemihydrated calcium sulphate, more commonly known as plaster of Paris (PoP).

PoP does not require the kind of hard-won skill that clay work requires. It is easy to cast in a mould, yields a smooth surface, dries quicker than clay, is friendlier to paint, and is much lighter (an important consideration when status-consciousness leads to larger idols) and the idols made with it are cheaper. But PoP does not dissolve readily, and it turns water hard.

Aside from the base material, the bright paints and dyes most artisans use contain toxic chemicals like mercury, zinc oxide, chromium, lead, and cadmium. They poison water bodies and aquatic life, and they can cause cancer, respiratory ailments, skin infections when they make their way back to humans via the seafood we eat or the water we drink.

Motivated by these concerns, organisations and individuals have been working to promote clay idols and natural dyes, as editions of this newspaper in Mumbai, Bengaluru and Tamil Nadu have reported.

The government of Goa is ahead of them, though: its Department of Science, Technology & Environment banned the manufacture, import and sale of PoP idols in 2008. (It was implementing Section 5 of India’s Environment (Protection) Act, 1986.)

Digambar Kamat, Chief Minister of the Congress government in power in 2008, recalls that there was “some movement” by environmentalists after Goa State Pollution Control Board (GSPCB) reports indicated that pollution of water bodies after the Ganesh festival was on the rise, but insists that the prime mover was his Environment ministry. Krishna Karapurkar, Deputy Manager, Marketing, of Goa Handicrafts, Rural and Small Scale Industries Development Corporation (GHRSSIDC), says that his organisation was one of the agencies that brought the issue to the notice of the government.

How successful has the ban been? It is implemented via a multi-agency approach — the GSPCB, the GHRSSIDC, the Excise and Commercial Tax department, the Transport department, and the police are involved — and uses both carrot and stick.

The state-owned GHRSSIDC incentivises Ganesh chitrashallas (as the manufacturing units are called) to not use materials harmful to the environment by giving them a subsidy of ₹100 per clay idol. Demand has been growing every year, Mr. Karapurkar said, with the number of subsidies going from around 37,000 (to 364 chitrashallas) in 2008, to over 53,000 (to around 500 chitrashallahs and artists) last year. He expects this year’s figure to cross 60,000.

The enforcement end includes measures like flying squads patrolling the borders to stop PoP idols from coming in ahead of the festival. The Commissioner of Excise is empowered to check vehicles or attach them with the help of police. GHRSSIDC and GSPCB officials in tandem inspect registered chitrashallas and withdraw subsidies and licences consent if they flout the ban.

Natalia Dias, senior legal officer of GSPCB’s Environment department says, “Adequate measures are underway, along with other departments, to ensure that these idols are not sold in the state.” Ms. Dias says that even if there is a suspicion of small quantities of insoluble material being mixed with clay, it is immediately reported to a District Magistrate, who directs collection of samples which are tested in GSPCB laboratories. But Ms. Dias was unable to name even one instance where this happened.

The evidence indicates that the ban has worked. GSPCB’s annual report for 2014–15, released recently, says that results of analysis of samples from

rivers and water bodies across the state before and after the festival revealed no increase in pollution. The report also said that GSPCB, at the directions of the National Green Tribunal, conducted a survey of chitrashallas to ascertain that no PoP idols are manufactured prior to the festival season.

Citizens, though, are sceptical.

Pandurang Nadkarni, a former chairman of Goa Board for Secondary and Higher Secondary Education, told The Hindu that the ban is a big joke. “Much ahead of the festival, around May, June, PoP idols come to Goa from neighbouring districts across the border in huge numbers.” Prerna Pawaskar, an environmental activist who, through her organisation Kalakriti, runs workshops teaching children to make clay idols, also dismisses the official claims, saying the market is flooded with PoP idols.

Manoj Naik, from Madkai village, on the banks of the Zuari river, in Ponda, central Goa, has been making Ganesh idols since he was 10 and started apprenticing under his late grandfather, Fondu Divto. He and his family were among the earliest to switch totally to clay. They now make around 240 clay idols of various sizes, and charge from ₹900 for the smallest idols to ₹10,000 for the largest. He complains that the government subsidy takes a long time to get. Other artists echo this, and say the paperwork required is tedious. Anup Priolkar, a social worker in Bandora-Ponda, casts doubts on both the transparency and efficacy of the subsidy.

And then there are the bootleg PoP idols taking business away. Mr. Naik says that while the ban is enforced strictly on the Goa-Karnataka border, a lot of idols come in from Maharashtra, particularly from Kolhapur. The entrepreneurs involved avoid the vigilance before the festival by simply bringing them in around June. Unscrupulous artisans in Goa just add a thin layer of clay to camouflage the idols, something laypersons wouldn’t be able to spot.

One more factor this year is the new Goods and Services tax regime. Mr. Karapurkar of GHRSSIDC says that there is no GST on the idols. But the creators say that there is 28% GST on the price of paints, which they will have to pass on to the consumer.

For the Remover of Obstacles, there seems to be a full wish-list still waiting for him in Goa.