Mobile ads may be more vulnerable to ad blocking than previously thought, with a study showing that 419m people globally are blocking ads on the mobile web, equivalent to 22 per cent of the 1.9bn global smartphone users.

According to research by PageFair, an estimated 408m people are actively using mobile ad blocking browsers that filter out advertising content by default, and even in-app advertisements are now vulnerable to being blocked, thanks to increasingly sophisticated efforts by ad blocking advocates.

Broken down into key markets, there are 14m monthly active users of mobile ad blocking browsers in Europe and North America, 38m in Indonesia, 122m in India and as many as 159m in China, as of March 2016.

The number of European and North American smartphone users who had downloaded content blocking and in-app ad-blocking apps from various app stores grew by 4.9m between September 2014 and March 2016.

“This is the start of something that will grow as more device manufacturers and web browsers follow the example of Apple, Samsung, ASUS, and browsers such as Opera,” said Dr Johnny Ryan, head of ecosystem at PageFair, in a blog post for the International News Media Association. “Our warning in this report is similar to those we gave in 2013 and 2014 regarding desktop ad blocking, which has now become mainstream.

“In contrast, publishers in the Asia-Pacific region are already feeling very significant losses from mobile ad blocking. Hundreds of millions of users are today using mobile browsers that block by default.

“Globally the message is that mobile, which agencies and publishers both view as a growth platform, has the same challenges as desktop. The Blocked Web – the portion of the web where people are blocking – is now both mobile and desktop, and this will be increasingly apparent to Western publishers over time.”