CHENNAI: A 24-year-old man has been arrested for watching and downloading child pornography on mobile for over two years in Ambattur.Police said S Harish of Kallikuppam near Ambattur, a science graduate, was arrested based on a tip from the National Crime Records Bureau (NCRB) that child pornography was being downloaded on a phone.Crime against Women and Children wing personnel verified the phone number with the list prepared by the National Centre for Missing and Exploited Children and confirmed that Harish was downloading child pornography.The Ambattur all-women police registered a case against him and detained him on Tuesday.Police found Harish used 500 IP addresses of different sites of child pornography. Initially, he watched such content at internet cafes.He decided to download the same on his mobile phone last year. He was booked under Sections 67 (B) of Information Technology Act (collecting, browsing and downloading material in any electronic form depicting children in obscene or indecent or sexually explicit manner) and 14 (1) of Pocso Act and remanded in judicial custody on Wednesday.During the course of interrogations Harish is said to have told police that he believed it was harmless to watch child porn.