Ipc 305 abetment of suicide

Charge sheet has been filled by police against me under ipc 305. I was worked as a Asst. Professor . My student commit suicide who has used his mobile at study time .No death note. It was 3 yrs back. Now police filled the charge sheet . Pl guide me how to proceed further . What is the next step ? How can i discharge the charge sheet or quash the charge sheet ?