The correct answer is option 2: Itai-itai. Itai-itai disease is caused by cadmium pollution. Cadmium is a toxic metal that is released into the environment from various sources such as industrial waste, mining, and agricultural practices. Itai-itai disease primarily affects the bones and kidneys.

Option 1: Minamata disease is caused by mercury pollution, not cadmium pollution. It is a neurological disorder caused by the ingestion of seafood contaminated with methylmercury.

Option 3: Fluorosis is caused by the excessive consumption of fluoride, usually through drinking water. It leads to the weakening and discoloration of teeth and, in severe cases, can affect bone health.

Option 4: Blue baby syndrome, also known as methemoglobinemia, is caused by the presence of nitrates in drinking water. It affects infants by reducing the oxygen-carrying capacity of blood.

So, the correct answer is option 2: Itai-itai disease, which is caused by cadmium pollution.