Most Google Adsense publishers were aware of the fact that Google adsense ads were not displaying on Opera mini and mobile browsers, which was effecting their earning potential. Surprisingly, since December 2014 onwards, adsense ads have started showing on Opera mobile browsers. Opera mini browser is the most popular mobile browser due to its light weight and compatibility with any mobile device, and website traffic almost accounts for 50% for any blogs nowadays. An example screenshot below -
Now with Google ads displaying on opera mini, Adsense publishers can expect an increase in their earnings. Though there is no official announcement from Google about this change if this is a permanent change or just temporary, it is expected that google has rolled out this development for good.
This development was long due as most of the website traffic comes from mobile devices, primarily from Opera. Google Adsense is the undisputed leader in advertising network and a boon for blog publishers.