Monthly Archives: September 2018

Hungry Ghost Festival – Part 3: Solutions

Previously, I mentioned how the Hungry Ghost Festival has an impact on our air quality and general hygiene. In this post, I will discuss the measures that have been or can be taken to mitigate these impacts.

A netizen’s suggestion to move with the times.

Comment extracted from here

Joss paper burning

In some residential areas, the burning bins provided have large holes that cause ash to be blown away easily.

The open-air design of these bins means pollutants are easily carried away by the wind.

Image courtesy of Imgur

In 2014, the government introduced eco-friendly joss paper burning bins with an improved closed top design, which prevents ash from flying out (The Straits Times, 2015). Air vents in the bin allow better airflow to facilitate complete combustions, reducing the amount of smoke and pollutants emitted (Science Learning Hub, 2009).

Left: Improved closed-top bin, Right: Old open-top bin

Currently, all three types of bins are still in use, but I think the government should replace all open-top bins with the improved closed-top ones given its effectiveness in reducing the spread of ash and smoke. Although these improved bins are more expensive, they are definitely a worthwhile investment for better air and health.

Joss Sticks

With regards to joss sticks, more research can be done to explore alternative methods to manufacture incense such that the byproducts from burning it are less harmful. For example, a study found that the use of oyster shells in producing incense can reduce particulate matter emission (Yang C.R. et al, 2012). The calcium carbonate content in oyster shells is resistant to burning, hence facilitating the effective burning of the other components in the incense (Yang C.R. et al, 2012).

Food offerings

After my last post on how food offerings can attract birds and rats, my friend Wan Teng shared on how her grandmother started to bring food offerings home in recent years to not waste food. This unconventional practice (Clarke, 2018) shows that there is no hard and fast rule when it comes to traditional rituals as mindsets and practices can change with time.

While it may be difficult to convince people to consume their offerings, a regulation can be put in place to mandate that individuals remove these food offerings once they are done with the rituals. This would retain the core of the rituals while solving the problems of hygiene. I’m sure the spirits will understand – because who wants to share their food with birds?

These are my thoughts on how we can mitigate the environmental problems from the Hungry Ghost Festival. If you have other suggestions, do share them with me in the comments section below.

With that, we have come to the end of the Hungry Ghost Festival series. While the Hungry Ghost Festival is more sombre than celebratory, I decided to discuss it as its impacts are very relatable to Singaporeans. Next week, I will move on to happy celebrations proper!



The Straits Times (Sep 6, 2015). Eco incense paper burners prove popular

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Science Learning Hub (Nov 19, 2009). What is smoke?

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Yang C.R., Ko T.H., Lin Y.C. Lee S.Z., Chang Y.F., Hsueh H.T. (Jul 28, 2012). Oyster shell reduces PAHs and particulate matter from incense burning

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Clarke, B. (Aug 3, 2018). A guide to the Hungry Ghost Festival: Don’t let the spirits catch you off guard this season

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Hungry Ghost Festival – Part 2: Pigeon Paradise

Last week, I discussed the air pollution that arises from the burning of offerings during the Hungry Ghost Festival here.

This week, I will talk about the hygiene issues that come with putting out food offerings on the streets. As part of traditional customs, people put out food items like fruits, biscuits and tea leaves as an offering to wandering spirits during the Hungry Ghost Festival. However, the common practice is to leave the offerings out overnight or until the cleaner removes them as it is taboo to tamper with or consume the offerings. The unattended food becomes a feast for wild animals like monkeys, birds, and rats, producing a slew of problems.

Pigeons help themselves to the food offerings on the ground.

Already, pigeon related issues are a major concern in residential estates. These birds are not fussy about their food and have acclimated to our urban environment such that they now thrive in large numbers.

Leaving food out in the open is akin to feeding the birds, which disrupts the ecological balance in the wild, allowing the pigeons to breed beyond what our natural environment can support (Loo and Kwok, 2018). In other words, there are more pigeons than the fruits on our trees can feed, due to these man-made food sources.

Furthermore, the availability of food causes the pigeons to congregate near human activity (Baker, 2018), encroaching into our living space. Once these birds establish that residential areas are a food source, they may start settling in as our neighbours. This is what happened at my parents’ flat where the roosting of pigeons under the air conditioner ledge is a problem. The pigeons leave the ledge full of feathers and droppings, creating a foul smell.

These wild birds and their droppings carry germs that may causes diseases, posing a great health risk and make our living conditions less desirable. The same can be said for rats, which also feed on these food left behind by pigeons.

Thus, the act of leaving food offerings out in the open has a detrimental impact on our living environment, health and ecological system. Next week, we will take a look at some possible measures to counter the environmental problems of the Hungry Ghost Festival.

EDIT: An earlier version of this post mentioned that pigeons play a role in pollinating trees and plants. This is not true as rock pigeons found in Singapore are granivores that feed on seeds.



Loo, A. and Kwok, J. (Aug 8, 2018). Feeding of wildlife causes host of problems

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Baker, J.A. (Mar 31, 2018). AVA urges people not to feed pigeons amid a sharp rise in feedback about the birds

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Hungry Ghost Festival – Part 1: Is that snow?

Welcome back to my blog!

Over the next two weeks, I will be covering the impacts of the Hungry Ghost Festival as per my observations and explore some possible measures to mitigate these impacts.

The Hungry Ghost Festival that just ended over the weekend is observed annually in the seventh month of the Lunar Calendar, where it is believed that spirits of the dead come to earth and roam around (Tan, 2018). It is customary for Taoists and Buddhists to put out offerings and light joss sticks on the street along their houses to honour wandering spirits and pray for peace and safety for their family members.

Even though my family observes this tradition, I was never involved in the process. To me, this time of the year just meant joss sticks on curbsides, “hell money” strewn all over the neighbourhood and a persistent burning smell.

In order to take a closer look at the effects of the festival, for the first time ever, I followed my grandfather as he performed the rituals on the last day of the hungry ghost festival and here is what we did.

Step 1: Find a patch of grass near our house

Step 2: Set up joss sticks, candles and food offerings as below

A typical offering setup includes candles, joss sticks and some food. 

 Step 3: The last step involves burning paper offerings like “hell money”

The inside of a typical burning bin, featuring my grandfather’s hand.

As I walked around my neighbourhood, I noticed that our offering setup was relatively simple and basic – some others had more than twice the number of joss sticks and candles. A strong smell of smoke permeated the air and ash drifted around with the wind, looking almost like snow.

In this photo, you can see the ash particles from the burnt offerings.

The most obvious impact of the Hungry Ghost Festival would be air pollution. Yesterday in class, I learnt about the different air pollution sources, one of it being area sources, which refer to multiple small sources that may be negligible individually but amount to considerable emissions as a collective whole. It occurred to me that the burning of offerings during the Hungry Ghost Festival is a perfect example of area sources.

While surveying my neighbourhood, I counted an average of two burning bins per HDB Block and most were in use. When we consider the combined emissions from the burning bins of HDB blocks across Singapore in the entire month, this could raise PM2.5 levels by 18-60% (Webster et al, 2015). High PM2.5 levels may cause respiratory and cardiovascular illnesses (The Straits Times, 2014) and the danger is amplified by our high population density.

Perhaps it is time that we think of environmentally friendly alternatives? Next week, I will look into some hygiene issues exacerbated by the Hungry Ghost Festival before moving on to possible solutions. Stay tuned!



Tan, C. (Aug 18,2018). Singapore’s Hungry Ghost Festival: what to do in the Lion City during the month-long event … and taboos to avoid

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Webster, R. D. et al (Sep, 2015). Annual air pollution caused by the Hungry Ghost Festival

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The Straits Times (Mar 12, 2014). Budget backgrounder: What is PM2.5 and how it affects air quality

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Dear reader,

Welcome to my blog! I am Si Hui, a Year 1 Environmental Studies student at the National University of Singapore.

Here’s a photo of me at Puaka Hill, Pulau Ubin!

On this blog, I will be exploring the environmental effects of celebrations and festivals.

My inspiration for this topic stemmed from my interest in waste. The idea of waste was something that never sat well with me. Perhaps it’s how I was brought up. I was taught to use things up before buying a replacement, and wasting food was frowned upon.

While reading up on waste, I discovered that Christmas is the most wasteful time of the year. Approximately 108 million rolls of wrapping paper were discarded in 2017 in the United Kingdom alone (Sheffield, 2016). This set me thinking about the environmental impacts of other celebrations, like the practice of dyeing the Chicago River green on St Patrick’s Day and the air pollution from New Year’s Day fireworks.

What are the ugly truths that lie behind our glamorous festivities?

Follow me on a journey around Singapore and the world to look into how various celebrations might have an impact on our environment and how our happiness today might lead to a hazardous tomorrow.



Sheffield, H (Dec 22, 2016). How to stop Christmas waste and the thousand of tonnes thrown away each year

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