You can get in contact with the institution calling the following number +91-33-2421-1970 or visit the Consulate in Calcutta, India
Japanese Consulate in Calcutta runs an inclusive range at 55, M.N. Sen Lane, Tollygunge, 700 040 yourself. If you want to omit the visit to the Embassy, simply apply for a Japan e-Visa online. Fill the application form within minutes from home.