Tilak Nagar - A youth sustained critical injuries as he was attacked for a petty reason in Chembur on Wednesday. According to police, two groups started fighting over a petty reason of not letting a youth to wear a ring in his finger. One of the youths from these groups sustained critical injuries in this incident and he has been admitted to Rajawadi hospital for medical treatment. Meanwhile, Tilak Nagar police have registered a case and arrested two persons in this connection. Police are searching for the other accused, informed police inspector Vijay Khaire.