In the 1950s and 1960s, Japan was severely affected by a disease caused by mercury pollution, called:

Minamata disease is a neurological disease caused by severe mercury poisoning. It was first identified in 1956 in the city of Minamata, in Kumamoto Prefecture, Japan.

Cause:

• The Chisso Corporation, a chemical company, released wastewater containing methylmercury into Minamata Bay from 1932 to 1968.
• The methylmercury accumulated in fish and shellfish (biomagnification), and people who ate the seafood were poisoned.
• Cats, birds and other animals in the area also showed symptoms; cats that seemed to "dance" and die were among the first signs.

Symptoms:

• Numbness in the hands and feet, muscle weakness, loss of coordination (ataxia), damage to vision, hearing and speech, and in severe cases, paralysis, coma and death.
• Children were born with congenital Minamata disease because the mercury passed from mothers to unborn babies.
• Thousands of people were officially recognised as victims, and many more were affected.
• A second outbreak occurred in Niigata Prefecture in 1965.

Minamata Convention on Mercury:

• It is a global treaty to protect human health and the environment from mercury.
• It was adopted in October 2013 at Kumamoto, Japan, and came into force on 16 August 2017.
• India ratified it in 2018.
• It aims to reduce mercury use, phase out mercury-added products (such as some thermometers, batteries and lamps), and control emissions from industries like coal power plants and gold mining.

Other pollution-related diseases:

• Itai-itai disease: caused by cadmium poisoning in Toyama Prefecture, Japan (1910s-1960s); it causes painful bone softening ("itai-itai" means "it hurts, it hurts").
• Blue baby syndrome (methaemoglobinaemia): caused by high nitrate levels in drinking water.
• Black lung disease (pneumoconiosis): caused by coal dust, affecting coal miners.
• Arsenicosis: caused by arsenic in groundwater; a serious problem in West Bengal and Bangladesh.
• Fluorosis: caused by excess fluoride in drinking water; common in Rajasthan and other states.

Other environmental disasters:

• Bhopal gas tragedy (1984): methyl isocyanate (MIC) leak from the Union Carbide plant.
• Chernobyl nuclear disaster (1986), Ukraine.
• Love Canal (USA, 1970s): toxic waste.

Why not the other options?

• ✗Itai-itai disease was caused by cadmium.
• ✗Blue baby syndrome is caused by nitrates.
• ✗Black lung disease is caused by coal dust.