Calcium carbide which is generally used as an artificial ripening agent, once dissolved with water produces acetylene. Acetylene is believed to affect the nervous system by reducing the oxygen supply to the brain. Ethylene which is a byproduct is also known to damage the neurological system.
Artificially ripened fruits differ from the natural ones since they are uniformly well colored and black patches may appear on them in 2 or 3 days.
In India the practice of artificially ripening is banned under the Prevention of Food Adulteration Act and violators are liable to undergo six month imprisonment and pay a fine of Rs. 1,000. But there are hardly any cases where traders or retailers are booked under this act.
It is necessary that we look before eating. While eating mangoes and apples, cut them into pieces rather than consuming directly. Fruits which have uniform color, for example a bunch of bananas having a uniform color is more likely to be ripened artificially. And lastly wash them before consuming.