Explained | What is a soft signal in cricket?

India beat England in the fourth T20I in a thrilling encounter at the Narendra Modi Stadium in Ahmedabad to level the series 2-2 and turn the fifth match on March 20 into a decider.

Invited to bat first, India scored 185 for eight in the stipulated 20 overs, with Suryakumar Yadav (57) and Shreyas Yadav (37) doing the bulk of the scoring.

In reply, England were halted at 177 for eight in their full quota of overs. All-rounder Ben Stokes top-scored for England with 46 off 23 balls while Jason Roy smashed a 27-ball 40 at the top of the order.

Surya Kumar Yadav, batting at the number 3 position, looked in fluent touch in just his second international. He amassed runs at will and held the innings together at a time when the English bowlers were threatening to dismantle India's middle-order.

The innings from 'SKY', as he is popularly known to fans, was laced with scintillating cover drives and backfoot punches but it was his eventual dismissal that has become a hotly-debated topic.

Yadav was given out caught in the deep by Dawid Malan off Sam Curran's bowling in the 14th over. It was not clear whether the low grab by Malan was a clean take but the third umpire Virender Sharma upheld the on-field umpire's 'soft signal' of out due to the lack of conclusive proof to the contrary.

Read more: Virat Kohli suggests 'I don't know' option for umpires after catch controversy

In cricket, the instances are aplenty where an on-field umpire's 'soft signal' influences the third umpire's verdict due to the absence of conclusive proof. Let's take a look at what a 'soft signal' means.

According to the International Cricket Council's rules, a 'soft signal' is a "visual communication by the bowler's end umpire to the third umpire (accompanied by additional information via two-way radio where necessary) of his/her initial on-field decision prior to initiating an Umpire Review." In most cases, the third umpire upholds the 'soft signal' (out or not out) of the on-field umpire if there is no conclusive evidence to overturn the first verdict.

Yadav, who was named man of the match for his 31-ball blitz, said that he had no problem with the call and took the decision in his stride. "It was a great opportunity for me to bat at number three for India. Yeah, I knew he would come a little short at me, I am really happy with the way things went. Regarding my dismissal, not really disappointed because few things are not in my control. Things that are in my control, I try to control that and things outside that are not in my hands," said Yadav after the match.

India skipper Virat Kohli said that on-field umpires should have the option to stay neutral in a TV referral. "When there's a half-and-half effort, the soft signal becomes more important. I don't know why there can't be an 'I don't know' call for the umpires," said Kohli on the decision.

"These are decisions that can change the course of the game, especially in these big games. We were on the receiving side today and tomorrow, it could be some other team. You want these ironed out and keep the game really simple and linear. It isn't ideal in high-pressure games and we want a lot of clarity on the field," Kohli added.

"How can this be out?" cricketer-turned-commentator VVS Laxman wrote on Twitter with a screenshot of Malan taking the catch. "When you are not sure whether the ball was taken cleanly after watching so many replays using top class technology and still go by the soft signal given by the on-field umpire - I think this rule needs to be revisited and changed."

Former England captain Michael Vaughan said the catch was clean but the 'soft signal' in cricket needed to be revisited. "I thought Dawid Malan took that catch," Vaughan told the cricket news website Cricbuzz.

"Once that soft signal had been given out, he (on-field umpire) had to give it out because he did not have enough evidence to prove that he hadn't caught it. I just don't like the soft signal in the middle for catches on the boundary."

England pacer Stuart Broad agreed and tweeted, "It's the 'soft signal' which is odd. Hard for off field umpire to overturn."