Market Failure — Data Response Practice

Edexcel IAL Economics Unit 1 (WEC11)

Stimulus

Dubai expands single-use plastics ban as Gulf sugar tax debate returns

The UAE's federal single-use plastics policy has moved into its next phase in 2025, with restaurants, delivery platforms and supermarkets across Dubai and Abu Dhabi now required to charge a minimum of AED 0.25 per plastic bag and eliminate single-use plastic cups, stirrers and cutlery from their operations. Officials estimate that around 11 billion single-use plastic bags were used annually across the country before the policy began tightening in 2024, and early data from Dubai Municipality suggests consumption fell by approximately 45% in the first year of the charge.

At the same time, a renewed policy debate has emerged in the Gulf Cooperation Council (GCC) around excise taxes on sugary drinks. The UAE and Saudi Arabia already apply a 50% excise on soft drinks and 100% on energy drinks, introduced in 2017. A 2024 Ministry of Health review reported that per capita consumption of carbonated soft drinks in the UAE declined by roughly 32% over the seven years following introduction, though diabetes prevalence remains high at an estimated 12.3% of the adult population. Analysts at regional think-tank Gulf Economic Review argue that the current rate is now under-correcting, given that private healthcare costs linked to obesity and type-2 diabetes in the GCC are estimated at over USD 25 billion per year.

Critics, including several food and beverage industry groups in the region, argue that the taxes are regressive, hitting lower-income expatriate workers hardest, and that producers have largely passed the cost through to consumers without significant reformulation of products.

Table 1: Selected indirect taxes and externalities, UAE market (2024 estimates)

Source: Composite of published government and industry estimates, 2024.

Questions

Question 1 (2 marks) — Define the term negative externality of consumption, using an example from the stimulus.

Question 2 (6 marks) — Analyse how the AED 0.25 charge on single-use plastic bags is likely to correct the market failure associated with plastic bag consumption in the UAE.

Question 3 (10 marks) — Evaluate the view that the current 50% excise tax on carbonated soft drinks in the UAE is the most effective way to correct the market failure caused by sugary drink consumption.

Model Answers

Question 1 (2 marks)

A negative externality of consumption is a spillover cost imposed on a third party when an individual consumes a good, which is not reflected in the market price. In the stimulus, the consumption of single-use plastic bags creates an external cost of approximately AED 0.18 per bag — for example, pollution of marine environments in the Gulf — which consumers do not pay for at the till.

Examiner note: Two marks requires the concept plus an applied example from the stimulus. A common mistake is to define a production externality or confuse it with a negative externality of production like factory emissions.

Question 2 (6 marks)

A negative externality of consumption occurs when the marginal social cost (MSC) of a good exceeds its marginal private cost (MPC), leading to over-consumption and allocative inefficiency at the free-market equilibrium. The AED 0.25 per bag charge acts as an indirect (Pigouvian) tax on the consumer, designed to internalise the estimated AED 0.18 external cost per bag.

Applied to the UAE case, because the stimulus gives a price elasticity of demand of -1.4 for single-use plastic bags, demand is price elastic. The 0.25 AED charge therefore causes a more-than-proportionate fall in quantity demanded. This is consistent with the roughly 45% reduction in consumption reported by Dubai Municipality in the first year.

The chain of reasoning is: the charge raises the private cost of consumption closer to the full social cost, which shifts consumer behaviour along the demand curve, which reduces the quantity consumed towards the socially optimal level, which in turn reduces the welfare loss triangle associated with over-consumption. The result is an improvement in allocative efficiency in the Dubai retail market.

Examiner note: Level 3 (5–6) answers explicitly link elasticity (-1.4) to the size of the behavioural response and reference the 45% fall. Level 2 (3–4) answers explain the theory of Pigouvian taxes but stay generic and do not quote data. The specific move that separates them is quantifying the impact.

Question 3 (10 marks)

The 50% excise on carbonated soft drinks in the UAE is intended to correct a negative externality of consumption, where private consumers under-value the long-run health costs of sugar consumption. Using the stimulus, the 32% fall in per capita consumption over seven years, combined with a price elasticity of demand of -0.6, suggests the policy has had a measurable effect. The tax raises the price paid by consumers, moving private costs closer to social costs and reducing quantity demanded towards the socially optimal level. In this sense, the policy has achieved part of its allocative-efficiency objective.

However, there are significant limitations. First, the PED of -0.6 is inelastic, which means that the 50% tax produces a less-than-proportionate fall in quantity demanded. The stimulus suggests that healthcare costs related to obesity and type-2 diabetes in the GCC are still above USD 25 billion per year, and adult diabetes prevalence remains around 12.3%. This indicates residual over-consumption and suggests the tax may be under-correcting. Gulf Economic Review's argument that the rate is too low fits this analysis.

Second, the tax is regressive. Because lower-income expatriate workers spend a larger share of their income on such drinks, the welfare burden of the tax falls disproportionately on them. This creates an equity–efficiency trade-off that is not resolved by the policy.

Third, alternative or complementary policies may be more effective. Regulation on sugar content (a reformulation mandate, as used in the UK soft drinks industry levy tier system) could shift the supply curve by forcing producers to reduce sugar per serving rather than relying on demand-side price signals. Information provision — such as traffic-light labelling or school-based public health education — could reduce information failure, addressing the underlying reason why consumers under-estimate harm.

Finally, government failure is a relevant evaluator. Setting the "correct" tax rate requires accurate estimates of external costs, which are uncertain. If the rate is set too high, it can create a welfare loss of its own through under-consumption.

Overall, the 50% excise has reduced consumption but is unlikely to be the single most effective instrument. Its effectiveness depends on whether it is combined with reformulation incentives and information campaigns, and on whether the regressive impact is offset. A judgement that the tax is necessary but not sufficient is better supported by the stimulus than either extreme view.

Examiner note: Level 4 (9–10) answers reach a clear conditional judgement ("the impact depends on…") supported by data (the 32%, -0.6, 12.3%, USD 25 bn). They also name at least one evaluator such as government failure, inelastic demand, or the equity–efficiency trade-off. Level 3 answers make both sides of the argument but fail to reach a justified conclusion. A common mistake is to argue the tax "doesn't work" without engaging with the 32% consumption fall.

Common Mistakes

• Confusing an externality of consumption with one of production. Fix: check who is generating the spillover — the consumer drinking the drink, not the bottling plant.
• Asserting that an indirect tax "always" fixes market failure. Fix: evaluate by referencing PED, regressivity, and information failure; without these the answer cannot reach Level 4.
• Quoting no data from the stimulus. Fix: every paragraph in a 10-mark question should include at least one specific number (32%, 45%, AED 0.25, -0.6, USD 25 bn).

Diagram Reference

This data-response uses the following diagrams from the Revvy Learn diagram library:

• negative-externality-consumption.svg — MPB, MSB, MPC=MSC, welfare loss triangle at free-market quantity
• indirect-tax-pigouvian.svg — upward shift of supply by the tax, new equilibrium at socially optimal quantity

(An elasticity comparison diagram — contrasting PED −0.6 vs −1.4 behavioural responses — is on the v2 diagram backlog.)