A teacher has been arrested after a std X girl student from a private school in Shirti village of Shirol taluka died due to poisoning at a hospital here on Tuesday. Police said the teacher, Nilesh Balu Pradhane, of Bhairewadi in Kurundwadallegedly gave the student, Sanika Mali, a pesticide which she mixed with water and drank in an attempt to fall ill and escape the SSC exams as she was not prepared for it.