Teacher:Generate a correct and concise answer for the question based on the words in the context.
Teacher: Now, understand the problem? Solve this instance: Context : Sendia massacre (Bengali: ) was a massacre of unarmed Bengali Hindus in Sendia village in undivided Faridpur district on 20 May 1971 by the Pakistan Army.
Question : When did Sendia massacre occurr?
Student:
20 May 1971