Even as China bars 1.4 billion citizens from Twitter, its local authorities are splurging on global advertising on the site — helping make the country the platform's fastest-growing overseas ad market and one of its largest non-U.S. revenue sources.

A review of publicly available government tenders, budget documents and promoted tweets from 2020 to 2022 shows local authorities and Chinese Communist Party propaganda offices for cities, provinces and even districts across the country have flocked to Twitter to buy ads.

The promotions, often outsourced by local governments to state media, pitched local attractions as well as cultural and economic achievements to an international audience, and were permitted under an exemption to Twitter's ban on state-media advertising.