PV Sindhu created history by winning her first ever silver at the World Championships at the Emirates Arena in Glasgow in the final of the women's singles. She added to her tally of two bronze medals from 2013 and 2014, losing out to Japanese shuttler Nozomi Okuhara in what will go down as one of the greatest badminton matches in the modern era. Both shuttlers gave it their all, with each point contested with incredible intensity. The first game was taken by the Japanese player 21-19 and Sindhu fought back with a game of her own, taking it at 22-20 on her fourth game point attempt. The second rubber ended with a mammoth 73-stroke rally, which was eventually won by Sindhu, as both shuttlers lay sprawled on-court after the point, exchanging some exquisite shots and displaying phenomenal stamina levels.Also read: Video: PV Sindhu wins incredible 73-stroke rally against Nozomi Okuhara in World Badminton Championships 2017 finalThe third also went the distance as both players lunged and jumped desperately as they tired out. There was palpable tension on each point and nerves were on edge, especially for Sindhu, who looked to calm herself down and take breaks during the points. It was becoming a regular feature for the Indian and after multiple warnings from the umpire on previous occasions, she was finally shown a yellow card in the third game.A yellow card is given for a breach of the Laws of Badminton, which generally include misconduct. Instances during which this becomes applicable include throwing a racket into the opponent's court, sliding under the net, leaving the court without the umpire's permission, coaching while the shuttle is in play and deliberately causing delay, which is the provision for which Sindhu was booked.Two yellow cards lead to a red card, for which players are docked points. In case of flagrant behaviour or misconduct, an umpire can also issue a black card, after consulting with the referee and disqualify the player/side from the match.Also read: World Badminton Championships 2017: Why Saina Nehwal was back on court just 16 hours after her previous encounterHere are some of the best reactions on social media from the incident:Sindhu gets a Yellow card for misconduct (wantedly delaying the play) !— Kiran (@IamIVK) August 27, 2017Don't loose hope pv sindhu keep going don't think of the warning and yellow card just keep fighting— satishnuli (@satishnuli) August 27, 2017Yellow card to Sindhu ???? somebody give water to the chair umpire????— WHY SO SERIOUS SAMMY (@SamNitian) August 27, 2017Yellow card in a #badminton match !! This chair umpair is really a strict school teacher to #Sindhu #badmintonworldchampionships— SRIKANTH ADEPU (@srikanthviru) August 27, 2017The match refree is trying to trend on twitter it seems. #Sindhu #YellowCard #BWF2017— Shahnawaz Khan (@shahnawazk) August 27, 2017Girls be like yellow card mila Sindhu ko. Chalo matching ho gya#PVSindhu— Andha Kanoon (@MaasoomTroll) August 27, 2017That Snickers Sindhu quickly gobbled in at the expense of that yellow card is going to be the difference. You heard it here first.— Vikalp (@20ncounting) August 27, 2017