"As a result, India topped the list of countries from which the most paid reviews emanated last year, with Russia dropping out of the Top 10", the report said.
Further, the company said its fraud investigators identified 65 new paid review sites and blocked submissions from a total of 372 different paid review sites last year.
Almost 1 million reviews submitted for inclusion on Tripadvisor -- equivalent to 3.6 per cent of the total -- were determined to be fraudulent by the website last year, the report said.
In its second transparency report -- the first was released in 2019 -- the travel guidance platform said 67.1 per cent of the fake reviews had been caught before making it on to the platform by its pre-posting moderation algorithm.
The report said: "While our overall review contributions dropped in line with the slowdown in travel, fraudulent submissions -- which of course are not predicated on real customer experiences -- did not follow the same trend. Our team remained vigilant and effective at catching would-be fraudsters, and as a result the proportion of reviews we rejected or removed increased compared with pre-pandemic 2018 figures."
While they may pose the biggest threat to the platform's integrity and those of the businesses on it, fake reviews are not alone in being removed. In total, more than 2 million review submissions (representing 8.6 per cent the total) were rejected or removed from the Tripadvisor platform, for instance because they included use of profanity.
While travel restrictions imposed by Covid led to a reduction in submitted reviews -- the number in August last year (approximately 4m) was half that in August 2018 -- the virus also posed other challenges, which Tripadvisor said led to its team manually assessing an additional 257,022 reviews, of which 46,145 were removed by moderators for violating posting guidelines, the report said.
They included reviews containing encouragement to ignore government guidelines, discouraging testing or spreading misinformation, with racially insensitive comments including references to the "China" or "Wuhan" virus or criticising a business for introducing Covid safety measures.