In total, around 30 unique ads appeared promoting child sexual abuse, although some of them were shared by multiple accounts.

The alias account was also shown around 20 ads featuring adult pornography.

The distribution of both child sexual abuse material and adult pornography are criminal offenses in India, while Meta’s policy states that ads must not contain adult nudity, genitalia or content that sexually exploits or endangers children. The BBC has reported all Telegram ads and channels to the Indian authorities.

One ad showed a boy and girl, both appearing to be about 12 years old, engaging in a sexual act.

Another showed a man hugging a girl, with text saying he was 52 years old and the girl was 12. “Click to see more,” it said, linking to a Telegram channel.

The BBC reported on an Instagram advert showing a very young girl crying, with text indicating that she had been sexually assaulted.

But 24 hours later, Instagram responded saying it had not removed the ad because “our review team found that the advertiser’s ad does not go against our community standards.”

Meta later told the BBC that “no system is perfect and our review process may not detect all policy violations.”

“We continue to run proactive detection technology on ads once they are published, and anyone can report an ad to us that they believe violates our rules,” Meta said.

He added that when he becomes aware of apparent child exploitation, he reports it to the National Center for Missing and Exploited Children (NCMEC), in compliance with the law. NCMEC is the global centralized reporting system for online child sexual exploitation.

We report two channels to Telegram for selling videos of child sexual abuse.

One of them was later removed and replaced with a message saying: “This group cannot be shown because it violated Telegram’s Terms of Service,” but the other continued to post new videos for sale.

Critics have previously accused the platform of not doing enough to prevent the sharing of criminal content.

The Dubai-based company is not a member of either NCMEC or the Internet Watch Foundation, which also works with most online platforms to find, report and remove such material.

Telegram told the BBC that the company uses both automated and human moderation to eradicate child sexual abuse material (CSAM) from the app and, as a result, says it has “virtually eliminated public dissemination of CSAM from its platform.”