what is ball tampering?

It was interesting to read about Shoaib Akhtar bringing up the ball tampering issue in his autobiography, “Controversially Yours”. His opinion is that ball tampering should be legalized, the rationale being that everyone does it and in a game which is so blatantly lopsided in favour of the batsmen, every little that the bowler can do to even the contest should be welcomed. So let us understand this a bit more. What is ball tampering? According to Cricket law 42, sub-section 3, legitimate treatment of the ball is restricted to polishing it without the use of any artificial substances. Therefore, bodily secretions like sweat and saliva are allowed to be used to shine the ball. The ball is also allowed to be polished on the clothes that the cricketers wear provided there is no artificial polishing or unusually abrasive material used. Use of a towel to clean mud off the ball is allowed under the umpire’s supervision. Therefore, the use of Vaseline, toffee induced saliva, and other such material to shine the ball is considered tampering. The use of zips, shoe nails, finger nails, bottle caps other sharp objects to roughen up the ball is considered tampering, and to alter the shape and prominence of the seam, using nails to pick the seam, or to alter the shape of the ball outside the natural scope of the game, is considered tampering.
The second question is, why tamper with the ball? I will not go into the physics of swing bowling. Suffice is to say that it is believed that altering the shape of the ball or making the seam more prominent, especially unevenly prominent, or tampering with the ball to increase the difference between the shiny and the scruffy sides influences air interaction with the ball and the pitch response to the seam, and can therefore provide prodigious swing and seam movement.
We’ve now very briefly looked at what ball tampering is and why some bowlers resort to it. In my next post, I will opine on whether it should be legalized or not.