Blue baby syndrome is caused by pollution by

The correct option is C Nitrate

Intake of water contaminated with nitrates can cause the Blue Baby Syndrome or Methemoglobinemia. In Methemoglobinemia, the oxygen-carrying capacity of the blood decreases gradually. Nitrates after reaching inside the body converted into another form called as Nitrites. Nitrites then react with Haemoglobin and form Methemoglobin. Methemoglobin affects the blood’s ability to deliver oxygen to cells. Blue Baby Syndrome is fatal for infants. Hence, the correct answer is ‘Nitrate’.