Carbon tax
Topic: Taxation: Direct and Indirect Taxes, GST and Global Tax Issues · NCERT: Beyond NCERT
Meaning
A carbon tax is a Pigouvian tax on the carbon content of fuels or on emissions of CO₂. The more carbon a fuel has, the higher the tax on it.
- Pigouvian tax: a tax on an activity that harms people outside the market deal.
It matters because burning fossil fuels harms the climate, but the person burning them does not pay for that harm. A carbon tax puts that cost into the fuel price, so people use less carbon-heavy fuel.
Formula: Private cost + carbon tax = Social cost, where tax per unit = marginal external cost (MEC). MEC is the extra damage caused by one more unit of emissions.
Explanation
Why a carbon tax is needed: the unpriced externality
- Externality: a cost or benefit that falls on people outside a market deal. Neither the buyer nor the seller pays for it.
- Negative externality: a cost pushed onto others. Greenhouse gas emissions are a classic example.
- Private cost vs social cost:
- Private cost: what the producer pays, such as wages, raw material and power.
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Social cost = private cost + external cost (the damage done to others).
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What goes wrong without a tax:
- The climate damage from coal or oil is not charged to the user.
- So fossil fuel looks cheaper than it really is.
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So too much of it is burnt.
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Where the idea comes from: A.C. Pigou, The Economics of Welfare (1920). A carbon tax is his idea applied to carbon.
How it works
- The ideal rate: tax per tonne of CO₂ = MEC.
- The polluter now "feels" the damage it causes.
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It cuts its emissions to the level that is best for society.
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Tax based on carbon content: coal carries more carbon than cleaner fuels, so it pays more tax. This pushes users towards cleaner fuels and better technology.
- Worked example (illustrative figures from the Pigouvian model):
- A steel unit's private cost is ₹100 per tonne. Its emissions cause ₹20 per tonne of damage (the MEC).
- The government puts a carbon tax of ₹20 per tonne on it.
- The unit's cost becomes ₹120, which equals the social cost.
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Some buyers now buy less steel or switch to cleaner steel, so emissions fall.
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Double dividend (two gains from one tax):
- Dividend 1: fewer emissions.
- Dividend 2: new revenue. It can be used to cut other, more distorting taxes, such as taxes on labour income that discourage work.
Types: explicit and implicit
- Explicit carbon tax: a tax that is openly called a carbon tax and charged per tonne of CO₂. Examples are Sweden and Canada.
- Implicit carbon tax: a tax that is not called a carbon tax but still raises the price of fossil fuels. India's high excise on petrol and diesel works as one.
Design problems
- MEC is hard to measure: governments usually guess a rate and then adjust it.
- Behaviour vs revenue: the better the tax works, the less revenue it brings.
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Emissions fall → the tax base shrinks → revenue falls.
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Pass-through and incidence: firms pass the tax to consumers through higher prices. Tax incidence means who finally bears the tax.
- Demand for fuel is price-inelastic (it barely changes when the price changes).
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So most of the tax falls on buyers.
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Regressivity: a regressive tax takes a larger share of a poor person's income than of a rich person's.
- Fuel forms a bigger share of poor households' budgets, so a carbon tax hits them harder.
- Remedy: return the revenue to the poor through cash transfers or subsidies.
In India
- No explicit carbon tax: India prices carbon implicitly, mainly through excise duty on petrol and diesel.
- Clean Energy Cess on coal (timeline):
- 2010: it began at ₹50/tonne on coal.
- 2016: it had risen to ₹400/tonne.
- 2017: when GST came in, it was subsumed (merged) into the GST compensation cess. Coal paid 5% GST + ₹400/tonne compensation cess [1].
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2025: the 56th GST Council recommended removing the compensation cess on coal and raising GST on coal from 5% to 18% [1].
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Why the 2025 change mattered [1]:
- Lower total tax on final users: the GST rate went up, but the fixed ₹400/tonne cess went away. For most coal, the total tax burden fell.
- Fixes the inverted duty structure: this is when inputs are taxed more than the output, so tax credits pile up unused.
- Coal producers paid 18% GST on services and machines but charged only 5% on coal.
- At 18%, they can now use those credits, which frees up their cash.
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Level playing field: the flat per-tonne cess hurt low-grade domestic coal more than imported coal. Removing it helps Indian coal compete and cuts needless imports.
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Where carbon pricing stands now: coal lost its separate "green" cess in 2025. Some carbon pricing remains through excise on fuels and through carbon markets, such as India's Carbon Credit Trading Scheme (CCTS).
Don't confuse with
- Cap-and-trade: here the government caps total emissions and firms trade permits. A carbon tax fixes the price of carbon and lets the quantity of emissions adjust. Cap-and-trade fixes the quantity and lets the permit price adjust.
- EU's CBAM (Carbon Border Adjustment Mechanism): a charge at the EU border on the carbon content of imports. A carbon tax is charged inside a country on its own fuels and emissions. CBAM is a trade tool that pushes exporters such as India.
- Implicit vs explicit carbon tax: India's fuel excise raises fossil fuel prices but is not levied per tonne of CO₂. Sweden and Canada levy an explicit tax per tonne of CO₂.
- Windfall tax: a one-time tax on unusually large profits caused by an outside shock, such as India's SAED. Its target is excess profit, not carbon content.
Prelims Hooks
- Carbon tax = a Pigouvian tax (A.C. Pigou, The Economics of Welfare, 1920) on the carbon content of fuels or on CO₂ emissions. Ideal rate = marginal external cost, so private cost + tax = social cost.
- Double dividend = lower emissions + revenue that can be used to cut other, more distorting taxes.
- Explicit carbon tax: Sweden, Canada. Implicit carbon tax: India's excise on petrol and diesel.
- Clean Energy Cess on coal: ₹50/t (2010) → ₹400/t (2016) → merged into the GST compensation cess (2017) → removed by the 56th GST Council (2025), with GST on coal raised from 5% to 18% [1].
- Trap: raising GST on coal to 18% lowered the total tax burden for most coal users, because the ₹400/t cess went away [1].
- Trap: a carbon tax fixes the price of carbon. Cap-and-trade fixes the quantity of emissions.
Mains Points
- Carbon pricing in India: implicit, not explicit:
- India uses fuel excise, and used the coal cess until 2025, instead of a clear per-tonne carbon tax.
- Removing the coal cess in 2025 corrected an inverted duty structure and helped domestic coal [1]. But it also weakened a direct price signal against coal.
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The trade-off is energy security and affordability on one side and climate goals on the other. Carbon markets (CCTS) and CBAM pressure now carry more of that burden.
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Equity and design:
- A carbon tax is regressive, because fuel is a larger share of poor households' spending, and fuel demand is inelastic.
- The "double dividend" allows a fix: use the revenue for transfers to the poor or to cut distorting taxes on labour.
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Its success should be judged by emissions cut, not by revenue, since revenue falls as the tax works.
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Global coordination:
- A carbon tax in one country can push production to countries without one.
- Border tools like the EU's CBAM try to stop this. For Indian exporters, a credible domestic carbon price may reduce exposure to such foreign levies.