The answer is simple. The fire of a burning corpse is physically purified ninety-one times and the maximum number of ceremonies are performed over it, with a view to purify it and lift the dross with which the fire of a burning corpse is doctrinally considered to be burdened with. In an electric crematorium, no fire is used. Many Parsis seem to think there is no fire used in an electric crematorium. Nothing could be further from the truth.
Electricity is itself a form of fire.
But, more than that, the process in an electric crematorium involves raising the temperature inside the furnace to more than 700 degrees centigrade a point at which the hydrocarbons of the body catch fire or self-ignite. Also, contrary to popular belief, electric crematorium is not such a hygienic system. All over the world, especially in advanced countries, people are concerned about the environmental pollution caused by electric crematoriums. Scrubbers and high chimneys may, only to a very limited extent, reduce, but not eliminate stench and fly ash. Closer to home, ask those who live around Chandanwadi in Bombay and Vaikunth in Poona, how they are forced to shut their windows each time the crematorium s turned on and a layer of soot forms over water buckets and linen put out to dry.