Hello Satyajit,

 Yes good spoken English is required to get selection in iim's. Because in Indian corporate world English is adapted as a common language and also to deal with other countries also. So you should be proficient in English. India is not a country like china, Germany and japan which prefers their language the most. In india there are huge number of languages of different regions. All have come to a common ground and given English as corporate language. 

Thank you