Which pollution causes Itai-Itai disease in human beings?

The correct answer is B, cadmium pollution. Itai-Itai disease was first identified in Japan among people who ate rice grown with water polluted by cadmium from mining waste. Cadmium damages the kidneys and softens the bones, causing fractures and such severe pain that the Japanese name itai-itai means ouch-ouch. Option A is wrong because mercury pollution causes Minamata disease, also first reported in Japan, which attacks the nervous system and causes loss of coordination and speech. Option C is wrong because arsenic in groundwater causes arsenicosis, marked by skin lesions and pigmentation, a serious problem in parts of West Bengal and Bihar. Option D is wrong because excess nitrate in drinking water causes methaemoglobinemia, the blue baby syndrome, in infants. Learn these four pairs together, since examiners almost always place them in the same question.