1. The beginning point
Prithvi Shaw gavc his urine sample on February 22, 2019 during the Syed Mushtaq Ali Trophy match between Mumbai and Punjab at Indore. The trace of Terbutaline was detected during a test at the National Dope Testing Laboratory in New Delhi. Subsequently, the BCCI provisionally suspended Shaw on July 16, as per a BCCI release. Shaw did not test his B sample and accepted the result of the test.
2. How Terbutaline entered Shaw's body
Shaw took a cough syrup over the counter prior to the Syed Mushtaq Ali Trophy in Indore. Instead of checking with a phyisician, Shaw went by the word given by his father and consumed the cough syrup suggested by the pharmascist. Shaw detailed the event in his letter to the BCCI and submitted that he did not remember the brand of cough syrup.
3. The BCCI decision
Though BCCI suspended Shaw, the governing body accepeted his explanation that he took the susbtance inadvertantly and it did not occur to him that the syrup woukd contain Terbutaline. Shaw also made it clear that the cough syrup was taken to get immediate relief from the "common cough and cold" than with any intention of enhancing his performance.
4. Shaw's ban: Why is it backdated
As per WADA regulations, consumption of Terbutaline can cause a maximum of two-year ban. But if an athelete has taken the banned substance inadvertently through a medicine, then the length of the ban can be reduced -- 0 to 8 months, 8-16 months or 16-24 months. The BCCI decided that Shaw consumed Terbutaline for "therapeutic" purpose and also considering his young age, 19, bracketed his ban in the 0-8 months category. It was backdated to February 22 because Shaw at no point contested the charge. Since Shaw has to mandatorily serve half the period of the ban, the sentence in effect started from July 16, the day when he was provisionally suspended by BCCI.