Players are barred, by Law 42.3, from rubbing the ball on the ground, interfering with its seam or surface, or using any implement that can alter the condition of the ball to thereby gain unfair advantage. There have been plenty of ugly incidents centring on accusations of ball-tampering through cricket's history: the John Lever "Vaseline" affair in 1976-77; the times England and New Zealand accused Pakistan of it in the early 1990s; Michael Atherton's admission that he used dirt to treat the ball against South Africa in 1994; and perhaps most infamously, the Oval Test of 2006 when Pakistan forfeited the match because they were accused of having tampered with the ball.
From WG Grace, with his penchant for delivering a running commentary on opposition players and umpires, to Steve Waugh's Australians and their tactic of "mental disintegration", sledging is almost as old as cricket itself. The Australians, from Dennis Lillee to Merv Hughes have been the acknowledged masters, but Asian exponents like Kumar Sangakkara are fast catching up
Over the years the endeavour has been to take pitches out of the equation for ODIs and Twenty20s, by making them flat and uniform, so that the toss does not play a crucial part in the shorter format. In Tests, though, the preparation of the pitch and its durability are much more significant, impacting the result and duration of the game. Quite naturally pitches and their preparation in the longer forms of the game evoke a lot of comment and often controversy.
For a game as steeped in tradition as cricket is, the question of how much to rely on technology is a perennial - and is now becoming increasingly complex. The Decision Review System has been controversial since it was first put in place
Cricket has never stopped evolving: from round-arm bowling becoming the standard, to the 15-degree rule for arm flexion while bowling. From the number of balls per over to the specifications of equipment - ranging from glove-webbing to bat handles - almost every aspect of the game is regulated. New rules are frequently put in place - especially in the shorter forms of the game, as in the case of Powerplays, free hits, and the tweaking of field restrictions.
As the popularity of T20 cricket rises, administrators are striving to improve the following of Test cricket through innovations such as day-night fixtures. The inaugural day-night Test in Adelaide was a commercial success but some challenges remain, such as the quality of the pink ball, dew, and player scepticism
Shane Warne's one-year ban for the use of a diuretic in 2003 was the first reported instance in cricket of the use of performance-enhancing drugs (as opposed to recreational ones, a la Ian Botham, and various Pakistani and South African cricketers down the years). In 2006 Shoaib Akhtar and Mohammad Asif were found guilty of using the banned steroid nandrolone
Cricket's biggest match-fixing scandal was unearthed in 2000, when Hansie Cronje admitted he had accepted money to throw matches. Soon players from other countries were implicated, among them Mohammad Azharuddin and Saleem Malik. Since then, allegations of fixing - including the new phenomenon of spot-fixing - have cropped up sporadically, and it has been acknowledged that bookmakers and the underworld have been active in trying to influence cricket results and specific moments in play. In 2010, scandal reared its head again when three leading Pakistan players were questioned by Scotland Yard and suspended by the ICC over spot-fixing charges.
The auction of two IPL franchises in March 2010 led to a string of allegations surrounding the league's operations and those of its stakeholders. The immediate fallout was the sacking of the league's creator Lalit Modi but the IPL has been at the centre of controversy ever since
As cricketers became more aware of their rights and the money they earned their boards, every team gradually moved to the contracts system, which would assure a player a certain amount of income for a year irrespective of an injury or an unforeseen drop in form. There has been a fair amount of controversy over the implementation of contract systems over the years: the ugliest it got was when several West Indies stars refused to play for their team because of a dispute over contracts. India, Zimbabwe and Kenya have had their share of contracts-related problems too.