Yes it is mandatory. You have 2 options, you can get the certificate at you can get the certificate from any government hospital nearby your home OR at any government hospital in Dhanbad (see the procedure below). My suggestion is to get that certificate from nearby hospital to avoid any consequences.I had applied for MTech and PhD at IIT (ISM), Dhanbad and both the times I was asked for Medical certificate.In case you forget to get the certificate and come to IIT (ISM), Dhanbad, you can go to Patliputra Medical College Hospital in Dhanbad and get your medical certificate. You have to get your X-Ray of chest (Rs 50) and reports of few tests like blood test (Rs. 20), HIV test (Rs.35), ENT test (Free of cost) and eye test (Free of cost) mentioned on the certificate. You have to show your Aadhar Card when you visit the hospital. In 3 days you will get all the reports with minimal charge of Rs. 105. Or else you can get the reports by paying Rs. 500 directly in 1 day :D (Donu2019t ask for the explanation :P). Your medical certificate will be signed by CMO (at Medical Office, Hirapur which is 5 Km from the hospital) after showing your reports.I hope this will help.