The ban follows Beijing police’s capture of phone dealers selling pornographic films on memory chips. Each chip could hold up to a 60 minute film, according to China’s Xinhua news agency.

Phone users who send pornography face fines of up to 3,000 yuan ($385) and two weeks in detention, while merchants caught selling such content will face between six months and three years in prison.

China has the world’s largest mobile phone subscriber population, with 461 million users.