Drishti's EVS Project

1Market-based climate policy

Carbon Trading

Definition

Carbon trading (emissions trading) is a market mechanism in which a regulator limits the total greenhouse gas that covered entities may emit and lets the right to emit be bought and sold. One tradable unit = 1 tCO₂e (one tonne of carbon dioxide equivalent).

Carbon dioxide emissions are a negative externality: the damage they cause is not included in the price of coal, oil or gas. Trading puts a price on that damage. The quantity of emissions is fixed by the regulator, and the price is discovered by the market.

Other gases are converted to CO₂e using their Global Warming Potential (GWP, 100-year): methane ≈ 27–30, nitrous oxide ≈ 273 (IPCC AR6). The idea goes back to Ronald Coase (1960) and J. H. Dales (1968); the first large test was the US Acid Rain Program for SO₂ (1995).

Bełchatów coal power station in Poland with plumes from its cooling towers and chimneys — Bełchatów, Poland, Europe's largest coal-fired power station and for years the single biggest emitter covered by the EU ETS.Photo: Petr Štefek, CC BY 2.5

Three types of trading system

Cap-and-trade

Absolute cap

A ceiling is set on total emissions. Allowances equal to the cap are given free or auctioned. Each year firms surrender one allowance per tonne emitted. The cap falls over time. Example: EU ETS.

Baseline-and-credit

Intensity target

Each plant gets a target in tCO₂e per unit of output (e.g. per tonne of cement). Beating it earns credits; missing it means buying credits. Output can still grow. Example: India's CCTS.

Offsets

Project credits

Verified reductions or removals from projects outside the capped sectors (wind, solar, forestry, methane capture) are issued as credits that others can buy. Example: Kyoto CDM, Verra, Gold Standard.

How cap-and-trade works

The total stays within the 160 t cap. The cut happens at Firm A, where it is cheapest, and Firm B pays Firm A for it.

Try it · Cap-and-trade simulator

Why trading lowers the cost of cutting emissions

Two factories each emit 100 t. Firm A can cut up to 60 t at ₹500 per tonne; Firm B can cut at ₹2,000 per tonne. Tighten the cap and compare the cost when each firm must cut equally with the cost when they can trade allowances.

Total cap140 t

Firm A · ₹500 / t to cut

Firm B · ₹2,000 / t to cut

40 tTotal cut required

₹50,000Cost if each firm cuts equally

₹20,000Cost with trading

₹30,000Saved by trading

The Kyoto and Paris mechanisms

Kyoto Art. 17

International Emissions Trading

Industrialised (Annex-I) countries could trade Assigned Amount Units with each other.

Kyoto Art. 12

Clean Development Mechanism

Projects in developing countries earned Certified Emission Reductions (CERs). India was one of the largest CDM host countries.

Paris Art. 6

The successor framework

Art. 6.2 allows country-to-country transfers (ITMOs); Art. 6.4 creates a UN-supervised crediting mechanism. Rules were largely settled at COP29, Baku, 2024.

Merits and limitations

Merits

Environmental certainty: the cap fixes the maximum quantity.
Cuts happen where they cost least.
Every tonne avoided has a market value, which rewards innovation.
Auction revenue can fund the clean-energy transition.
Systems can be linked across countries.

Limitations

Volatile prices make investment planning hard.
Over-allocation can crash the price (EU ETS, 2007).
Carbon leakage: industry may move to places with no carbon price.
Offsets may lack additionality or permanence.
Needs strong monitoring, reporting and verification (MRV).

Case study 1.1

The EU Emissions Trading System

Launched on 1 January 2005, the EU ETS is the world's first major international cap-and-trade market. It covers about 10,000 power stations and factories in the 27 EU states plus Iceland, Liechtenstein and Norway, along with aviation inside Europe and, since 2024, shipping.

2005Launch year

~10,000Installations covered

−50%Covered emissions vs 2005, reached in 2024

−62%Legal target for 2030

Emissions in covered sectors (2005 = 100)

2005

100

2023

53

2024

50

2030 target

38

Source: European Commission and EEA. 2023 saw the largest one-year fall (about 17% for stationary installations). Verified 2025 data show a further 1.3% drop.

2005–07
Phase I. Pilot. Allowances were over-allocated because no verified data existed, and the price fell to almost zero by 2007.
2008–12
Phase II. Aligned with Kyoto. The 2008–09 recession left a large surplus.
2013–20
Phase III. Single EU-wide cap, auctioning as the default; Market Stability Reserve from 2019.
2021–30
Phase IV. Faster cap decline under "Fit for 55"; shipping added; Carbon Border Adjustment Mechanism (CBAM) on imports.

Lessons

Accurate baseline data are essential. A cap set above real emissions creates no scarcity and no price.
Most of the cut came from replacing coal power with renewables. In 2024 renewable generation rose 8% and coal generation fell 15%.
A predictable, falling cap gives industry the confidence to invest in low-carbon technology.

Case study 1.2

India: from PAT to the Carbon Credit Trading Scheme

India's first market scheme was Perform, Achieve and Trade (PAT), launched in 2012 by the Bureau of Energy Efficiency (BEE). It set energy-efficiency targets for energy-intensive plants; units that beat their targets earned tradable Energy Saving Certificates. PAT grew to cover more than 1,000 units in 13 sectors.

The Energy Conservation (Amendment) Act, 2022 allowed the government to create a carbon market, and the Carbon Credit Trading Scheme (CCTS) was notified in June 2023. It has two parts. Under the compliance mechanism, obligated plants get binding emission-intensity targets for 2025–26 and 2026–27 against a 2023–24 baseline and earn or buy Carbon Credit Certificates (CCCs). The offset mechanism registers voluntary reduction and removal projects.

~490Obligated entities in 2025–26

7Sectors: aluminium, cement, chlor-alkali, pulp & paper, refining, petrochemicals, textiles

31 Jul 2026First compliance deadline

2×Penalty: twice the average CCC price

BEE administers the scheme, MoEFCC notifies the targets, Grid Controller of India runs the registry and CERC regulates trading on the power exchanges, where compliance trading was expected to begin around October 2026. The intensity-based design lets output grow while emissions per unit fall. It supports India's NDC to cut the emissions intensity of GDP by 45% from 2005 levels by 2030, and the national goal of net zero by 2070. Critics note that intensity targets do not guarantee absolute cuts.

2Pigouvian taxation

Carbon Tax

Definition

A carbon tax is a levy on the carbon content of fossil fuels, or directly on greenhouse gas emissions, set as a fixed price per tonne of CO₂e.

It is a Pigouvian tax (A. C. Pigou, 1920): a tax equal to the external damage of an activity, so the polluter pays the full social cost. It follows the Polluter Pays Principle (Rio Declaration, Principle 16).

A carbon tax fixes the price and lets the quantity of emissions adjust. Trading does the reverse. Because every fuel's carbon content is known, the tax converts simply into a rate per litre or per tonne. Burning one litre of petrol releases about 2.3 kg CO₂.

A row of offshore wind turbines at Middelgrunden near Copenhagen — Middelgrunden offshore wind farm, Denmark. Carbon pricing makes low-carbon power such as wind more competitive with fossil fuels.Photo: Kim Hansen, CC BY-SA 3.0

Design choices

Where

Point of taxation

Upstream at refineries, mines and importers (few taxpayers, simple), or downstream at power plants and factories.

How much

Rate and path

A rate that starts moderate and rises on a published schedule gives households and firms time to adapt.

Revenue

Recycling

Returned as dividends, used to cut income tax (the "double dividend"), or spent on clean energy and adaptation.

Try it · Carbon tax calculator

What a carbon tax adds to everyday fuels in India

Move the slider to set a tax per tonne of CO₂. The table uses standard emission factors, so the results are approximate. Sweden's rate of about US$126 per tonne is over ₹10,000.

Carbon tax₹2,000 / tCO₂

Carbon tax compared with carbon trading

Criterion	Carbon tax	Carbon trading
What is fixed	Price per tonne	Total quantity of emissions
What varies	Quantity emitted	Allowance price
Certainty given	Price certainty for business	Environmental (quantity) certainty
Administration	Simple; uses existing tax system	Complex; registries, auctions, MRV
Revenue	Predictable	Depends on price and share auctioned
Main risk	Wrong rate misses the target	Volatility, over-allocation
Examples	Sweden, Norway, Finland, Switzerland, Japan, Singapore	EU, China, California, Korea, India

Merits and limitations

Merits

Clear, stable price signal.
Easy to administer and hard to game.
Predictable revenue.
Reaches scattered sources such as cars and home heating.

Limitations

The emission outcome is uncertain.
Regressive: poorer households spend more of their income on energy, unless revenue is returned to them.
Hurts trade-exposed industry and can cause leakage.
Politically hard: France's 2018 "gilets jaunes" protests and Australia's 2014 repeal.

Case study 2.1

Sweden's carbon tax, 1991 to the present

Sweden introduced its carbon tax in 1991 as part of a major tax reform that cut income tax and shifted the burden onto pollution. It applies mainly to fossil fuels used for heating and transport. Industry covered by the EU ETS is exempt to avoid double pricing, so the tax covers about 40% of Sweden's emissions.

SEK 250Rate in 1991 (≈ US$26 / t)

SEK 1,190Rate from 2020 (≈ US$126 / t), the world's highest

−27%Greenhouse gas emissions, 1990–2018

+50%Real GDP per capita, 1990–2019

Where it worked

The largest effect was on heating. District-heating networks switched from oil to biomass and waste, and homes replaced oil boilers with heat pumps. In transport, Andersson (2019) estimated that the carbon tax alone cut CO₂ by about 4.9% a year over 1990–2005, and by 10.9% when combined with VAT on fuel.

Where it fell short

Exemptions and lower rates for manufacturing, farming and forestry meant the tax fell mostly on households and transport. Emissions from industrial processes rose about 8% between 1990 and 2010. Economists argue that one economy-wide rate would have been cheaper. Sweden's hydro and nuclear power also helped.

Lessons

Start moderate and raise steadily to build public acceptance.
Pairing the tax with income-tax cuts reduced political opposition.
Emissions respond most where cheap substitutes exist, such as biomass and heat pumps.

Case study 2.2

India's Clean Environment Cess on coal

India has no economy-wide carbon tax, but in 2010 it placed a Clean Energy Cess of ₹50 per tonne on coal, lignite and peat, both domestic and imported. This worked as an implicit carbon tax on its most carbon-intensive fuel. The proceeds went to the National Clean Energy Fund for renewable energy and environmental projects such as Namami Gange.

2010
Clean Energy Cess introduced at ₹50 / tonne.
2014
Raised to ₹100 / tonne.
2015
Raised to ₹200 / tonne.
2016
Raised to ₹400 / tonne and renamed the Clean Environment Cess, equal to roughly US$3–4 per tonne of CO₂.
Jul 2017
Abolished with the arrival of GST and replaced by a GST compensation cess of ₹400 / tonne. Its revenue went to compensating states, not to clean energy.

Lesson

A low implicit carbon levy can raise substantial revenue, but its environmental purpose fades when the money is diverted to general budget needs.

3Atmospheric chemistry

Primary & Secondary Pollutants

Primary pollutants

Emitted directly into the air from an identifiable source, in the same chemical form in which they are released. Examples: SO₂ from coal burning, CO from vehicle exhaust, soot and fly ash.

Secondary pollutants

Not emitted directly. They form in the atmosphere when primary pollutants react with each other or with O₂, water vapour and OH radicals, often driven by sunlight. Examples: ground-level O₃, PAN, H₂SO₄ aerosol.

From exhaust pipe to smog

Major primary pollutants

Pollutant	Main sources	Effects
Sulphur dioxide (SO₂)	Coal and oil burning, smelting, refineries	Bronchoconstriction, worse asthma; forms acid rain and sulphate aerosol
Nitrogen oxides (NO_x)	High-temperature combustion in vehicles and power plants	Airway inflammation; forms ozone, PAN, nitric acid and nitrate PM
Carbon monoxide (CO)	Incomplete combustion, vehicles, biomass	Forms carboxyhaemoglobin and cuts oxygen delivery to tissues
Volatile organic compounds	Fuel evaporation, solvents, paints, vegetation	Some are carcinogenic (benzene); form ozone and organic aerosol
Particulate matter (PM₁₀, PM_2.5)	Road and building dust, diesel soot, fly ash, crop burning	Reach deep into the lungs; heart and lung disease; haze
Ammonia (NH₃)	Fertilisers, livestock waste	Reacts with acids to form ammonium sulphate and nitrate particles
Heavy metals (Pb, Hg, Cd)	Smelting, coal burning	Nerve and kidney damage; build up in food chains

How the secondary pollutants form

Ground-level ozone (O₃)

NO₂ + hν (λ < 420 nm) → NO + OO + O₂ + M → O₃ + MNO + O₃ → NO₂ + O₂

In clean air these three reactions cancel out. When VOCs are present, their peroxy radicals convert NO back to NO₂ without using up ozone (RO₂ + NO → RO + NO₂), so ozone builds up. Ozone damages lung tissue and cuts crop yields.

Acids and fine particles

SO₂ + OH → HOSO₂ → SO₃ + HO₂SO₃ + H₂O → H₂SO₄NO₂ + OH + M → HNO₃ + M2NH₃ + H₂SO₄ → (NH₄)₂SO₄

H₂SO₄ and HNO₃ cause acid rain (pH below 5.6). Neutralised by ammonia, they form ammonium sulphate and nitrate particles in the PM_2.5 range. VOC oxidation adds secondary organic aerosol. PAN (CH₃C(O)OONO₂) is a strong eye irritant.

Two kinds of smog

Feature	Classical (London)	Photochemical (Los Angeles)
Main pollutants	Primary: SO₂, smoke, soot	Secondary: O₃, PAN, aldehydes
Source	Coal burning	Vehicle exhaust (NO_x + VOCs)
Weather	Cold, damp, foggy; inversion	Warm, dry, sunny; inversion
Chemistry	Reducing	Oxidising
Peak	Winter mornings	Summer afternoons
Effects	Bronchitis, high mortality	Eye irritation, lung damage, crop loss

Aerial view of Mexico City under a brown layer of photochemical smog — A brown band of photochemical smog trapped under a temperature inversion over Mexico City.Photo: Fidel Gonzalez, CC BY-SA 3.0

Why the distinction matters. Primary pollutants can be controlled at the source with flue-gas desulphurisation, electrostatic precipitators, catalytic converters and cleaner fuels. Secondary pollutants can only be controlled by cutting their precursors, often across a whole region, because they form downwind. India's National Ambient Air Quality Standards (2009) set limits for 12 pollutants, both primary (SO₂, CO, Pb) and secondary (O₃).

Case study 3.1 · Primary pollutants

The Great Smog of London, 5–9 December 1952

An anticyclone settled over London, bringing calm air and a strong temperature inversion that trapped cold fog near the ground. In the bitter cold, homes burned large amounts of cheap, high-sulphur coal. Coal-fired power stations at Battersea, Bankside and Fulham, and the diesel buses that had replaced the trams, added more.

With no vertical mixing, smoke and sulphur dioxide built up for five days. Visibility fell to a few metres. SO₂ dissolved in fog droplets and oxidised to sulphuric acid, a primary pollutant turning into a secondary one. Each day about 1,000 t of smoke particles and 370 t of SO₂ were released, producing roughly 800 t of sulphuric acid.

Nelson's Column barely visible in the Great Smog of 1952 — Nelson's Column, Trafalgar Square, during the smog.Photo: N T Stobbs, CC BY-SA 2.0

5 daysDuration, 5–9 Dec 1952

~4,000Excess deaths recorded at the time

10–12kTotal deaths in later re-analysis

100,000+People with respiratory illness

Outcome

The Beaver Committee report led to the Clean Air Act, 1956. It created smoke-control zones, subsidised the switch from coal for home heating, and moved power stations out of cities with taller chimneys. It was strengthened in 1968. The Great Smog is regarded as the founding event of modern air-quality law.

Case study 3.2 · Primary and secondary

Delhi's winter smog

Delhi skyline hidden by thick grey smog in 2019 — Delhi under winter smog, 2019.Photo: Prami.ap90, CC BY-SA 4.0

NASA satellite image of smoke from crop fires spreading across north India — NASA satellite view of smoke from stubble fires drifting over north India, November 2013.Image: NASA, public domain

In October and November, PM_2.5 in Delhi often exceeds ten times the national 24-hour standard of 60 µg/m³. On 1 November 2019 the Supreme Court-mandated pollution authority declared a public health emergency, closing schools and halting construction.

Primary

Vehicle exhaust (NO_x, CO, black carbon), road and construction dust, industrial SO₂, and burning of paddy stubble in Punjab and Haryana after the kharif harvest.

Secondary

SO₂, NO_x and farm ammonia form ammonium sulphate and nitrate; VOCs form organic aerosol. Cold, humid nights favour ammonium nitrate. Secondary aerosol is a large share of winter PM_2.5.

Weather

Low temperatures, weak winds and a shallow mixing layer trap pollution near the ground. North-westerly winds carry smoke from the stubble fires.

Response

Graded Response Action Plan (GRAP), National Clean Air Programme (2019), BS-VI fuel (2020), closure of city coal plants, the Commission for Air Quality Management (2021), Happy Seeder machines and bio-decomposer sprays. Because much of the haze is secondary, precursors, including farm ammonia, must be controlled across the whole Indo-Gangetic plain.

4Methylmercury poisoning

Minamata Disease

Definition

Minamata disease is a neurological syndrome caused by severe poisoning with methylmercury (CH₃Hg⁺) from eating fish and shellfish contaminated by industrial wastewater. It is named after Minamata city, Kumamoto Prefecture, Japan, where it was identified in 1956.

Why methylmercury is so toxic. It is fat-soluble and crosses the blood–brain barrier and the placenta. It binds to sulfhydryl (–SH) groups in proteins; a methylmercury–cysteine complex mimics the amino acid methionine and is carried into the brain. Its half-life in the body is about 50–70 days.

In water, bacteria in sediments turn inorganic mercury into methylmercury (biomethylation). It is absorbed faster than it is excreted, so it bioaccumulates in each organism and biomagnifies up the food chain.

Map of Minamata showing the Chisso factory, Hyakken Harbour, Minamata Bay and the Minamata River — Effluent routes from the Chisso factory: first into Minamata Bay through Hyakken Harbour, and from 1958 into the Minamata River mouth, which spread the poisoning along the coast of the Shiranui Sea.Map: Bobo12345, CC BY-SA 3.0

Biomagnification of mercury

Symptoms

Sensory

Numbness and tingling (paraesthesia) in hands, feet and around the mouth.

Motor

Cerebellar ataxia: unsteady gait, poor coordination, tremor, slurred speech.

Vision and hearing

Constriction of the visual field (tunnel vision) and hearing loss.

Severe cases

Mental disturbance, paralysis, coma and death.

Congenital

Babies of exposed mothers were born with cerebral-palsy-like disability, even when the mother showed few symptoms.

Brain damage

Visual cortex, pre- and post-central gyri, and cerebellar granule cells are hit hardest.

Case study 4.1

Chisso Corporation and Minamata Bay

From 1932 to May 1968 the Chisso chemical factory, Minamata's main employer, made acetaldehyde by hydrating acetylene with a mercury(II) sulphate catalyst. A side reaction produced methylmercury, which was discharged untreated into the bay. Between about 70 and 150 tonnes of mercury were released over 36 years.

HC≡CH + H₂O —(HgSO₄, H₂SO₄)→ CH₃CHO · side product: CH₃Hg⁺

36 yrsMercury discharge, 1932–1968

12 yrsFrom discovery (1956) to official recognition (1968)

2,265Certified victims in the Minamata area by 2001

10,000+Received payments under the 1995 settlement

Early 1950s
Dead fish float in the bay, seabirds fall from the sky, and cats convulse and die ("dancing cat disease").
1 May 1956
Dr Hajime Hosokawa of the factory hospital reports an "unknown disease of the central nervous system", the official date of discovery.
Jul 1959
Kumamoto University researchers name organic mercury from the factory as the cause.
Oct 1959
Hosokawa's "Cat 400" fed on factory wastewater develops the disease; Chisso keeps it secret, installs a treatment unit that does not remove methylmercury and pays small "sympathy money" while denying liability.
1965
A second outbreak, Niigata Minamata disease, appears on the Agano River, caused by the same process at a Showa Denko plant.
1968
Chisso stops the mercury process in May; in September the government officially names Chisso's methylmercury as the cause.
1973
Kumamoto District Court finds Chisso negligent and liable.
1977–1997
About 58 ha of polluted sediment is dredged and reclaimed; the bay's fish are declared safe and the nets are removed in 1997.
2004 / 2009
Supreme Court holds the national and Kumamoto governments liable; a 2009 Special Measures Act offers relief to more victims.

Minamata Disease Municipal Museum building — Minamata Disease Municipal Museum, built on land reclaimed from the polluted bay.Photo: hyolee2, CC BY-SA 3.0

Memorial cenotaph to Minamata disease victims in a landscaped park — Cenotaph to the victims of Minamata disease, on the reclaimed land of Minamata Bay.Photo: STA3816, CC BY-SA 3.0

Global significance

The 12-year delay between discovery and recognition shows the cost of ignoring the precautionary principle.
It set the precedent that companies and governments can be held liable for pollution damage, and fed into Japan's Basic Law for Environmental Pollution Control (1967) and Environment Agency (1971).
The Minamata Convention on Mercury (adopted 2013, in force 16 August 2017) bans new mercury mines, phases out mercury in products such as thermometers, batteries and lamps, and in processes including acetaldehyde production. India ratified it in 2018.
India's own warning is mercury contamination from a thermometer factory at Kodaikanal, Tamil Nadu (closed 2001).

5Chronic cadmium poisoning

Itai-itai Disease

Definition

Itai-itai disease ("ouch-ouch disease") is severe chronic cadmium (Cd) poisoning that damages the kidneys and softens the bones (osteomalacia with osteoporosis), causing fractures and intense pain. It occurred in the Jinzu River basin, Toyama Prefecture. In 1968 it became the first disease officially recognised in Japan as caused by pollution.

Cadmium is a soft heavy metal found as an impurity in zinc ore (sphalerite, ZnS). It is released by zinc, lead and copper mining and smelting, and used in Ni–Cd batteries, pigments and electroplating. The IARC classifies it as a Group 1 human carcinogen.

A lump of pure silvery cadmium metal — Cadmium metal (Cd, atomic number 48).Photo: Hi-Res Images of Chemical Elements, CC BY 3.0

How cadmium destroys bone

Kidney

Absorbed Cd binds to metallothionein in the liver. The complex is filtered and stored in the proximal tubules of the kidney. Above about 200 µg/g in the renal cortex, tubules fail: β₂-microglobulin, glucose and amino acids leak into urine (a Fanconi-type syndrome).

Bone

Damaged tubules waste calcium and phosphate and cannot activate vitamin D (1,25-dihydroxyvitamin D₃), so less calcium is absorbed from food. Bones become soft and brittle. Iron, calcium or protein deficiency increases Cd absorption.

Symptoms

Severe pain in the lower back, hips and legs; a waddling gait; deformed bones and a loss of height of up to 20–30 cm from spinal compression; and repeated fractures, with 72 recorded in one patient. Kidney failure often caused death. Most victims were post-menopausal women who had borne many children, because pregnancy, breastfeeding, menopause and poor nutrition all raise calcium demand and cadmium uptake.

Case study 5.1

Cadmium pollution of the Jinzu River basin, Toyama

Kamioka zinc smelting plant in a mountain valley with steam rising — Zinc smelting plant at the Kamioka Mine, Gifu Prefecture, upstream of the Jinzu River.Photo: もんじゃ, CC BY-SA 4.0

The clear Jinzu River flowing through a green mountain valley — The Jinzu River today. Cleaner wastewater treatment has brought cadmium back to near-natural levels.Photo: RESPITE, public domain

The Kamioka Mine, run by Mitsui Mining and Smelting Co., had been worked for lead, silver and zinc since the 16th century. Output grew sharply in the 20th century, especially for wartime zinc. Cadmium-rich waste went into the Takahara River, a tributary of the Jinzu. Downstream, farmers used the river to irrigate paddy fields and for drinking, cooking and washing.

Cadmium built up in the paddy soil, especially near irrigation inlets, and was taken up by rice. Rice from the polluted area held about 0.7–1.0 ppm Cd, roughly ten times the level elsewhere. Japan's current limit for brown rice is 0.4 ppm.

~1912First cases reported

1968Officially recognised as a pollution disease

~200Certified patients, mostly women

863 haPaddy soil restored, 1979–2012

c. 1912
An unexplained bone disease appears in villages on the lower Jinzu.
1946
Local doctor Noboru Hagino begins studying it and presents it to a medical conference in 1955.
1957–61
Hagino, later with Jun Kobayashi, shows from analysis of water, soil, rice and tissue that cadmium from the Kamioka Mine is the cause.
May 1968
The Ministry of Health and Welfare officially blames cadmium from the mine.
1971–72
The Toyama District Court, and on appeal the Nagoya High Court (Kanazawa branch), find Mitsui liable. It was the first of Japan's Four Big Pollution lawsuits to be decided.
1979–2012
863 ha of contaminated paddy restored by burying topsoil under clean soil, at a cost of over ¥40 billion.
2013
Mitsui formally apologises and agrees to relief for people with cadmium-related kidney damage.

Lessons

Heavy metals in farm soil persist for decades; prevention at source is far cheaper than clean-up.
Low-dose exposure through a staple food can affect a whole community, hitting the most vulnerable hardest.
A determined local doctor and independent scientists overcame corporate and official denial.
It led to cadmium standards for rice and water and the Agricultural Land Soil Pollution Prevention Law (1970).

Minamata and Itai-itai compared

Aspect	Minamata disease	Itai-itai disease
Toxic agent	Methylmercury, CH₃Hg⁺	Cadmium, Cd²⁺
Place	Minamata Bay, Kumamoto (also Agano River, Niigata)	Jinzu River basin, Toyama
Polluter	Chisso Corporation (acetaldehyde plant)	Mitsui Mining & Smelting (Kamioka Mine)
Route into people	Fish and shellfish	Rice and drinking / irrigation water
Key process	Bioaccumulation and biomagnification in the sea	Build-up in paddy soil and uptake by rice
Organs hit	Brain and nervous system	Kidneys and bones
Main symptoms	Numbness, ataxia, tunnel vision; congenital cases	Bone pain, osteomalacia, fractures, kidney failure
Most affected	Fishing families; unborn babies	Older women who had many children
Recognised	Found 1956; cause recognised Sept 1968	Reported c. 1912; recognised May 1968
Legacy	Minamata Convention on Mercury (2013)	Cadmium food limits; soil pollution law

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Environmental Studies Project

Carbon Trading

Three types of trading system

Absolute cap

Intensity target

Project credits

How cap-and-trade works

Why trading lowers the cost of cutting emissions

Firm A · ₹500 / t to cut

Firm B · ₹2,000 / t to cut

The Kyoto and Paris mechanisms

International Emissions Trading

Clean Development Mechanism

The successor framework

Merits and limitations

Emissions in covered sectors (2005 = 100)

Carbon Tax

Design choices

Point of taxation

Rate and path

Recycling

What a carbon tax adds to everyday fuels in India

Carbon tax compared with carbon trading

Merits and limitations

Where it worked

Where it fell short

Primary & Secondary Pollutants

From exhaust pipe to smog

Major primary pollutants

How the secondary pollutants form

Ground-level ozone (O3)

Acids and fine particles

Two kinds of smog

Minamata Disease

Biomagnification of mercury

Symptoms

Itai-itai Disease

How cadmium destroys bone

Symptoms

Minamata and Itai-itai compared

Quick Quiz

Ground-level ozone (O₃)