2019 Yes https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7158895/#:~:text=from%20the%20results.-,Background%20noise%20level,from%2053%20to%2066.4%20dBA. Saravanan, Gomathi Asia Observational Exposure Study Students Elementary (K-5) Middle/Jr High (6-8) High School (9-12) Noise Acoustics Classroom noise Hearing loss India Reverberation Schools for the deaf Teacher voice The mean noise level and reverberation time in all classrooms exceeded recommended maximum levels. The measured SNRs were not optimal for children with hearing impairment. Observations of the classrooms revealed that acoustical treatments were inadequate.