Illegal Delivery in Cricket: What are the Rules? (With Explanation)

The topic of illegal delivery in cricket is one of the most controversial, and often one of the least understood. It has been a root cause of many hotly debated controversies in the cricket world. So, in this article, we take a look at the meaning of illegal delivery, exact rules, their explanation, a few examples, and exceptions.

But first, what is an illegal delivery in Cricket? A delivery is considered illegal in cricket if a bowler is “Throwing” or “Chucking” the ball rather than bowling it. Furthermore, if a bowler bowls an “Underarm” delivery, it is also considered an illegal delivery in cricket.

But how is it determined whether the bowler is actually chucking or throwing the ball rather than bowling a legitimate delivery? There is a lot more that goes on in order to determine the legitimacy of the bowling action. Let’s look at it in detail below –

1. Illegal Bowling Action

If there is anything that a bowler is afraid of in the game of cricket – it is being called for an “Illegal Bowling Action”. An illegal bowling action is when a bowler extends or straightens the elbow more than 15 degrees while releasing the ball as compared to the angle of the elbow when the bowling arm reaches the shoulder level in the delivery action.

The 15-degree measurement is taken by measuring the difference between the angle created due to the bent in the elbow when the bowling arm first reaches the shoulder level and then the angle created due to the bent in the arm at the time of releasing the ball through the course of the bowler’s bowling action.

If the difference in the two angles is more than 15-degrees, such a bowling action is also known as “Throwing” or “Chucking” the ball and is considered illegal.

This may sound a bit confusing at first, but, it will be a lot easier to understand once we’ve seen the examples shared in the article below –

1.1 15-degree Rule Explained

As mentioned earlier in the article – the difference of the angle of bend of the elbow at the time of release of the ball should not be more than 15 degrees than the angle of bend of the elbow at the time the arm reaches shoulder level in the delivery action.

Let’s understand this with the following example –

15-degree rule of chucking or throwing in cricket explained
Image Courtesy “The Cricket Digest”

Using the above image, we can understand the 15-degree rule better. As per the 15-degree rule, we need to make a note of angle of elbow bend at two points during the course of completing the action of the delivery.

First, we need to make a note of the angle of bend when the bowling arm reaches the shoulder level as represented in the image (a). In this example, the angle of bend at this point is 35 degrees.

Next, we need to note the angle of bend of the elbow when the ball is released. This is represented in the Image (b) above. Notice how the elbow straightens as the bowler proceeds through his bowling action. In the above example, the angle at this point in action is 20 degrees.

Thus, the bowler in the above example has a difference of 15 degrees (35 – 20 degrees). Hence, the bowling action represented in the image above shall be deemed legal.

However, in a situation where the difference of the two angles is higher than 15 degrees, the action will be considered illegal.

1.2 Can a Bowler bowl with a Bent Elbow or a Bent Arm?

One of the biggest misunderstanding when it comes to chucking is that people believe that a bowler can not bend his arm when bowling. If he does so, it is chucking. This was certainly the case prior to the early 1990s.

However, as per the 15-degree rules explained above, it is not illegal to bowl a delivery with a bent arm. As long as the bowler starts the delivery action with a bent arm and it remains bent until the ball is released, it is okay.

The problem occurs when a bowler starts his bowling action with a bent arm, but straightens it at the time of delivery in order to generate more pace or spin on the ball. As stated above, in such a scenario, the degree of straightening should not exceed 15 degrees.

1.3 History Preceding the 15-degree rule

Up until the 1990s, even a little flexing of the bowling arm was considered illegal. However, research conducted in the 1990s in England revealed that virtually all bowlers tend to flex or extend their arm to at least some degree. As a result of this, ICC realised that implementing the strict laws of the game which banned any flexing of the arm was virtually impossible to implement.

As a result of the above study, ICC came out with new regulations that allowed tiered tolerance thresholds for straightening the arms while bowling. The accepted tiers of flexing thus implemented were – 5 degrees for a spin bowler, 7.5 degrees for a medium pace bowler and 10 degrees for a fast bowler.

A later study in the early 2000s revealed that many of the most elite fast bowlers in the world of cricket had, on average, a bend of 9 degrees in their arm. Some cricketers even recorded elbow straightening of 10-15 degrees! What was really surprising was the fact that virtually none of these bowlers ever had any problem regarding the legality of their bowling action. Even their bowling actions looked completely normal to the naked eye.

Thus, ICC realised that the “Tiered threshold” implemented in the 1990s had little or no scientific merit. Subsequently, after considering biomechanical findings of nearly 130 fast and spin bowler, a new 15 degree limit was chosen. ICC also realised that the bowling actions considered illegal often measured the bend angle in the range of 20 – 30 degrees which was well above the 15 degree limit.

1.4 What Happens when a Bowler bowls with an Illegal Action during a Match?

If a bowler is found to be bowling with a suspicious bowling action, the appeal can be made by the batsman. The umpires shall assess the fairness of the delivery and accordingly take action. Similarly, an umpire can also call out the bowler if an umpire deems the action of the bowler illegal.

Umpires Discussing a suspected bowling action
Umpires discussing the suspected bowling action of a bowler

In such a situation, the procedure followed by the umpire is as follows –

  • The umpire shall first call out a “No Ball”, and inform the other umpire for the reason for his call.
  • It is the duty of the umpire at the striker’s end, primarily, to assess the fairness of the bowling action of the bowler and to call out the “No Ball”. However, even the umpire at the bowler’s end is allowed to take the same action.
  • Once the “No Ball” has been called, the umpire at the bowler’s end shall –
    1. Warn the bowler with a first and final warning. This warning is applicable throughout the innings.
    2. Inform the captain of the bowling side about the warning and the reason for his actions.
    3. Also, inform the two batsmen about the occurrence of the event.
  • A bowler, who has been given a warning for chucking, can continue to ball throughout the rest of the innings as long as he doesn’t get called for a suspected bowling action again in the innings. However, if any of the two umpires feel that any of the further delivery by the same bowler seems to have an illegal bowling action, the umpires shall then –
    1. Call out a “No Ball”
    2. Suspend the bowler immediately from bowling further in the innings.
    3. Inform the two batsmen & the captain of the bowling side
  • The remaining over of the suspended bowler shall be completed by another bowler who hasn’t bowled the previous over. The bowler thus completing the over shall also not be allowed to bowl the immediate next over.
  • The two umpires together shall, as soon as possible after the match, also inform the ICC and the cricket boards of the two teams about the occurrence of the event. Post which, appropriate action shall be taken against the individual concerned, the captain or even the team as deemed necessary.

1.5 Can a Bowler Ever Bowl Again? What happens after the Appeal?

If a bowler’s bowling action has been reported for a suspicious bowling action, the bowler will have to get his bowling action assessed at an ICC accredited bowling action testing centre.

Suspected Bowling action being tested at ICC testing facility
Suspected bowling action being tested at an ICC accredited testing facility

Such bowling assessments at a testing centre are designed to measure the amount of elbow bend occuring during the bowler’s action. There are several parameters that are looked at during the assessment.

The bowlers, during such an assessment, is required to bowl every single type of delivery that a bowler bowls during an international match. Failing to do so can lead to the suspension of the bowler from all international cricket formats.

Following the assessment, a detailed report is produced by the testing centre and it is sent to selected members of the ICC panel reviewing the player with suspected bowling action. Based on this report, ICC decides the legality of the bowling action and the decision is then communicated to the respective cricket board and to the bowler.

If the bowling action is found to be illegal, the player will be suspended from bowling in all international cricket formats. However, the player can work on rectifying the bowling action, and reapply for testing. The complete process is repeated again, and only if the bend angle in the action is found within limits, the player is allowed to bowl again.

1.6 Exceptions to the Rule –

While the process for evaluating the bowling action of a bowler is quite rigorous, there have been found to be exceptions to the rule.

Hyperextended Elbow –

There are players who may appear to have a suspected action even if they have a less than 15 degree extension in their elbow. Particularly, bowlers who tend to have an hyperextend elbow.

Shoaib Akhtar Elbow Hyper Extension

Shoaib Akhtar had a significant hyperextension in his elbow. This means he was able to extend the arm backward which created an optical illusion that he was chucking. Subsequently, after going through rigorous testing, the defect was identified.

Indian bowler RP Singh was called for a suspected bowling action, and was later found to have an hyperextension in the elbow. He was subsequently cleared for bowling.

Muthiah Muralitharan Controversy

Another interesting case was that of the Sri Lankan spin bowling legend Muthiah Muralitharan. He was called for chucking numerous times, some even after he was cleared by the ICC.

Video showcasing Murali’s being given a No Ball for chucking even after being cleared
(Hint – watch the video from 1 minute 30 seconds)

During the testing, it was found that Murali seemed to have a birth defect and had an abnormal bend in the elbow by default creating an optical illusion that he was chucking. During the biomechanical report, it was stated that Murali was not bending his arm any more than most of the bowlers around and well within the allowed limit.

Even though Murali was subsequently cleared by the ICC, the report of the testing never cleared his bowling action in the eyes of the critics and purists of the game.

Murali further went on to wear a brace with a steel rod around his elbow to showcase the natural bend and to prove his point. (Have shared this interesting video below)

Murali bowling with a brace made of steel rods to validate the deformity

Despite such measures by Murali, the critics have been split right in the middle when it comes to the legitimacy of Murali’s bowling action.

2. Is Underarm Bowling Illegal?

For some, the answer may be obvious. But many of us may not realise the original style of bowling a cricket delivery was “Underarm Bowling”. In fact, it was commonly in use until up to 1910. Post which, most bowlers continue to ball overarm. However, this style of bowling continued to remain legal in the laws of cricket. This was only after the Trevor Chappel Underarm controversy in 1981 that the rules were changed.

2.1 Underarm Bowling Controversy

On 1st February 1981, when Australia was playing New Zealand in an ODI match, New Zealand needed six runs to tie the match from the final ball of the 50th over. Greg Chappell, the then Australian captain, fearing the possibility of conceding an opportunity to win the match ordered the Trevor Chappell, (his brother) to bowl underarm

Trevor Chappell subsequently rolled the ball along the ground to prevent the New Zealand batsman from any chance of hitting a six of the last ball to tie the match.

2.2 So, is it illegal?

There was a lot of debate around the controversy with most people calling it a disgraceful event. After the game, as a direct result of the incident, underarm bowling was banned in cricket by the International Cricket Council as “not within the spirit of the game.”

Although, the underarm bowling is illegal, if the captains of the two teams mutually agree before the start of the match to bowl underarm, it shall be deemed legal in such a scenario

ICC Rules of Illegal Delivery

Now, although the underarm bowling is illegal, it can be allowed upon mutual agreement of the captains of the two participating teams before the start of the match.

Related Questions –

Q. Why is chucking illegal in cricket?

Chucking in cricket is not allowed as this creates an unfair advantage to the bowler. The act of chucking while delivering the ball includes straightening the arm to about 20 to 30 or more degrees. This allows a fast bowler to generate additional speed while bowling. For a spin bowler, it can allow the bowler to generate more revolutions on the ball thus resulting in additional spin of the ball giving an unfair advantage to the bowler.


Chucking is illegal in cricket. It provides an unfair advantage to the bowler. Furthermore, if a bowler has a suspicious bowling action, it can be hard for him to correct it as it is something that the player has been used to ever since he started practising.

The rules around an illegal delivery are also often misunderstood. I hope this post has helped you understand the rules, and the nuances of chucking in cricket.

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Shrot Katewa

Shrot is an avid cricket fan! He has played and endorsed the sport ever since he was in School. In fact, he played as a professional cricketer represented his state team in National Indoor Cricket Championship held in Pune, India. Shrot loves the game, loves talking to other people who play the game and share his learnings with other interested individuals. He is the founder of This website is a culmination of his desire to help others understand this wonderful Game of Cricket!

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