The labourers of a colony used to drink cheaper alcohol from unauthorised sources. This alcohol contained some methanol. One day a few labourers complained of drowsiness and pain, and loss of eyesight after consuming the liquor. Their family members took them to the hospital and the doctors tried to treat them. One of the labourers died and other complained loss of their eyesight. As a student of science, how would you analyse this serious situation ? How does drinking of cheap alcohol cause problem ?